eBay – eBay is likely the largest and most well-known marketplace for selling collectibles like baseball cards online. Selling on eBay gives you access to millions of potential buyers and the auction-style format can generate interest and competition that drives up prices. EBay will also take a percentage of the final sale price as a fee. You’ll need to create a seller account, take high quality photos of your cards, write detailed descriptions, and properly package and ship any items that sell.

Sportlots – Sportlots is a dedicated sports card marketplace. They have a large buyer base and can help you sell individual cards or your entire collection. Like eBay, they take a fee from the final sale price. Selling on Sportlots gets your cards in front of collectors specifically looking to buy cards. They also handle photography, descriptions, payments, and shipping for an added fee. This makes the process simpler but you’ll receive less money per sale.

COMC – Cardboard Connection (COMC) allows you to sell baseball cards through a consignment model. You send your cards to them, they professionally photograph and list them, handle transactions and shipping. For modern cards they typically take a 19-21% commission fee. For vintage/valuable cards it’s lower at 13-15%. Unlike eBay and Sportlots, you don’t have to list items yourself but you also don’t set the prices – COMC handles negotiations with buyers. Shipping is also slower than individually handling sales yourself.

Collector forums/groups – Sites like Sports Card Forum, Blowout Cards Forum, and Facebook groups are platforms where serious collectors congregate. You can sell individual cards or entire collections through want/sell listings. This allows you to tap into collectors specifically looking for what you have available. You need to know current market values, take your own photos/write descriptions, arrange payment/shipping on your own. Scams are also more likely without buyer/seller protections of major marketplaces.

Local card shops – If you live near a collectibles/card specialty shop, they may buy entire collections outright or be willing to consign individual high-value cards through their storefront. You won’t get top recent eBay prices but it’s convenient and secure compared to shipping. Many want first shot at local collections before they go online too. Smaller shops won’t have the buyer demand of larger sites.

Collector/dealer direct – Serious, established collectors and dealers sometimes buy entire collections to later break up and sell individually to maximize profits. While you likely won’t make as much as selling piecemeal yourself, it’s the simplest option since you don’t have to take photos, list items, mail packages. Payment is usually via check or wire transfer. It’s important to do research on potential buyers/their reputation to avoid scams. Meet face-to-face if possible when significant money is involved. You’ll also have less visibility into where items ultimately sell and for how much.

Factors like collection size, card value ranges, preferred involvement level, speed of sale, and goals for maximizing profit all factor into the best fit marketplace. eBay or dedicated websites like Sportlots/COMC are best for average collections, while high-value collections may have more luck seeking an established collector/dealer to buy outright. Researching recently sold cards on sites is also recommended to understand fair pricing wherever you choose to sell. Authenticating/grading valuable cards is another way to potentially boost prices, though involves extra time/cost.

eBay is likely the largest and most well-known marketplace for buying and selling sports cards online. Some key points about selling on eBay:

eBay allows you to list individual cards or entire card collections. You can sell common cards for just a few dollars or rare valuable cards for hundreds or thousands.

When listing cards on eBay, it’s important to take high quality photos, thoroughly describe the card condition and grade if applicable, and be upfront about any flaws. Honestly disclosing details helps buyers feel confident and may attract more interested bidders.

eBay collects a final value fee from the seller, which is usually around 10% of the final sale price plus a 30 cent per order listing fee. So be sure to factor these fees into your minimum price.

As the largest online marketplace, eBay offers the biggest potential buyer base. But also means more competition from other sellers. Make sure to properly research recently sold prices to set a competitive list price.

For valuable rare cards, using eBay’s authenticity guarantee program provides buyers additional confidence and may attract higher bids. You’ll pay a fee but eBay handles authenticating the item.

Be responsive to questions from potential buyers. Most issues can be avoided with clear communication. Having positive seller feedback is important on eBay.

Another popular option for sports card collectors is the peer-to-peer marketplace app called COMC, which stands for Cardboard Connection. Here are some key things to know about selling on COMC:

COMC allows you to send your entire card collection to them for consignment scanning and listing. They photograph and list each individual card online.

Unlike eBay where you set the price, COMC uses recent market sales data to price each card automatically based on condition, player, year, etc. You agree to accept whatever price a buyer pays.

Selling on COMC avoids the time commitment of listing individual cards on eBay. But generally will yield slightly lower sale prices since COMC takes a percentage cut rather than fixed fees like eBay.

COMC charges 9% of the sale price plus $0.49 per card for basic consignment service. Upgrading to higher price point tiers lowers the percentage taken but increases the per card fee.

COMC has become one of the largest online sports card marketplaces and is very well known within the hobby. Large database of active buyers.

Downside is you have to ship your entire collection to COMC rather than selling individual cards yourself directly from home on eBay. Also less control over pricing and photos.

Another good marketplace option, especially for very high end and rare cards, is PWCC Auctions. Some key points about PWCC:

PWCC specializes in high value vintage cards, autographs and game used memorabilia with a minimum suggested consignment value of $1,000.

After consigning your items, PWCC handles photography, copy writing, promotion and running both traditional timed online auctions as well as live in-person auctions.

Since the focus is on rare six and seven figure cards, PWCC has developed an internationally recognized buyer base of serious collectors and investors.

Major downside is they only take on a limited number of monthly consignments and charge an industry high 22.5% commission plus applicable buyer fees on the hammer price. Only makes sense for truly rare expensive items.

PWCC provides the expertise and marketing to achieve maximum prices. But the high commission means it only pays off if your card or collection can reasonably sell well above other mainstream market options like eBay once fees are considered.

EBay typically makes the most sense for commonly found and lower end cards thanks to competitive fees and large buyer pool. COMC provides an easy consignment solution for entire collections. And PWCC auctions are best suited to six and seven figure vintage rarities. Properly researching each platform is important to decide which will offer the best overall net return. With some experience, education, and effort sellers have many good options to choose from.