First, generate more codes:
Then get a coupon for them:
You can give the coupon to other people or buy gifts with it. (services only, not t-shirts)
Sorry this took so long... we had to deal with cleaning the database in cases where people used fradulent credit cards to buy $1000 of paid accounts and get lots of invite codes that way. We also had to do some stats on what exchange rate made sense and the trade-offs in the dozen different things we could do, and then add support for the "intangible coupons" we decided on. (Coupons that can only be used for services... not tangible items.)
Anyway, the exchange is $0.50 for each of first 10 codes, then $0.25 thereafter, with a cap of $25, which is a year of paid time.
If you find any bugs with this tool, report them here and whitaker will look into it.