I just ordered some stuff and the codes that I had were expired. I started to input some similar numbers and BINGO, one hit.  SPG169.  I put in SPG and a 1 then 2 more semi-random numbers.  They seem to like double numbers like 77 and so forth. Also 1 and 9s for the last number.  Unlimited number of times that you can try inputing codes.  Most are of the 10% or $10 off per $100 spent variety.  Also try hitting the already a member button when checking out.  It automatically gave me the discount.  Good Luck!