A higher number is not always the better offer. Compare whether each shop is pricing the same group of cards, paying cash or trade credit, taking all bulk or only highlights, and settling immediately or after a review period. Start by finding category-fit buyers through the card shop directory and specialty hubs. Then ask for offers in a form you can compare: key cards, sealed product, graded cards, bulk, and any items the shop is excluding.
Adjust for convenience and risk. A slightly lower immediate cash offer may beat a higher consignment estimate if you need certainty. A higher trade-credit offer only wins if the shop has fairly priced inventory you actually want. The trade credit versus cash guide and card shop buylist guide explain how stores think. Avoid turning the process into an auction based on incomplete information; instead, ask polite, specific questions and choose the offer whose terms you understand.