AffiniPay Ranks No. 1328 on the 2015 Inc. 500|5000 with Three-Year Sales Growth of 158%. Austin, TX- August 24, 2015 – AffiniPay, the premier payment provider for associations and the legal industry, was ranked No.2396 on Inc. magazine’s seventh annual Inc. 500|5000, an exclusive ranking of the nation’s fastest-growing private companies.