Currently, PB offers 2% back when using earnings for purchases (down from 5% originally). This is not enough incentive for me to use my earnings here. Two cents on the dollar is nothing. Five cents on the dollar is nothing (even if a bit more). At current rates, I'd have to spend $50 to get $1 back. On other sites, I can can get at least one free book ($7) and be well over half way to a second for that amount of money. Which sounds like the better deal: a free $7 book, or $1 off your next purchase? (Especially since other sites also offer free shipping with minimum purchase.)

An increase in the percentage back would improve the use of PangoBucks, and would keep more money on the platform. A standard incentive of at least 10% ($1 back for every $10 spent) would increase the number of users who spend their earnings to purchase on PB rather than go where the rewards are better. Also, adding a tiered incentive (eg: 10% on first $50, %15 on $75+, %20 >= $100) would definitely encourage sellers to buy more and keep their money on PB. This would make PB much more competitive with larger sites and draw customers. The increased sales would be a win-win for both PB and the sellers.