I bought these and they've been great to play with and not so expensive. They hold a good amount of data and they are compatible with most phones, unlike the 1k models.

http://www.amazon.com/gp/aw/d/B00GYM3SG6/ref=mp_s_a_1_1?qid=1431780525&sr=8-1&pi=AC_SX110_SY165_QL70&keywords=Kamor%C2%AE+NFC+Tags+ON+SALE+-+Topaz+512.