Everyday, all day and night formula checks sell on ebay.  They can sell upward of 70-80% or more of the face value of the check.  From a buyers perspective the biggest problem that causes you to lose potential bids on your auction is confusing descriptions.  Here are 3 ideas on how to make the most of your auction and keep your message clear. 

1. Is it a coupon or a check? 
Checks bring in the most profit.  Don't confuse potential bidders by calling them 'coupon checks'.  It will make people shy away from your auction.  I am guessing you are probably trying to attract bidders who are searching for the words 'formula coupon' as well as searching for 'formula checks'.  If anything make it clear and say 'formula checks, NOT formula coupons'. 

2.  A picture is worth a thousand words...or in this case a few more bucks!
Because the sale of these is almost a guarantee, it is easy to think you don't need a picture...well you're wrong.  Many of the manufacturers have coupons in the same increments that they have checks.  So if you list a '$7 coupon check' it may be confusing and bidders don't want to take the chance on your auction that it is a coupon and not a check.  Erase all doubt and take a picture.  It's free to add one picture to your auction and you only need one.  The pic doesn't really even have to be a great one.  Just so one can determine if it's a check or a coupon. 

3.  Give expiration dates for each check. 
I've seen auctions that in the description says something like 'Ten $5 checks with expiration dates from x to y."  With x being already expired.  Be specific.  Many people wouldn't take a chance on this auction.  Maybe 9 are expired and 1 has a future expiration date.  Who can be sure how many are expired?  The bidder doesn't know and in this case what they don't know WILL hurt you.  Be specific and list the dates for each check.  It really won't take that much longer. 

Thanks and I hope this helps.