Are you buying the towels? Are you buying her a couple rolls of stabilizer? What would you pay for personalized towels from a nice shop? I think $5 per towel is on the low side considering the cost of stabilizers, her thread and her time and expertise. I think for all 12 towels $100 is certainly within range.
Check out the prices on this web site:
http://www.personalizationmall.com/Towels-c93.lp