Cheapest parts on amazon and place to buy pie
Ethernet adapter - https://www.amazon.com/Caxico-Ethernet-Network-Adapter-Tablet/dp/B011E6GA1Q
Sd card (comes with adapter) - https://www.amazon.com/Sandisk-Ultra-Micro-UHS-I-Adapter/dp/B073K14CVB/ref=gwm_tlc_pi?pf_rd_s=blackjack-personal-1&pf_rd_t=Gateway&pf_rd_i=mobile&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=02FQ89HMESF3K30BKBR0&pf_rd_p=608ee3fa-bc0f-4174-a3ba-e9dd4600db22&pd_rd_i=B073K14CVB
Pie - https://www.adafruit.com/product/2885
The shipping for the pie is 5$ from usps and if you have prime you can get the sd card and ethernet adapter the next day free shipping plus i already have a wall adapter and micro usb cable so i dont need to buy that but if you do heres the cheapest one and its free next day delivery if you have prime https://www.amazon.com/Android-Micro-Charger-Cable-Adapter/dp/B07TH2NCBL/ref=mp_s_a_1_fkmr0_1?keywords=chris+bliss+micro+usb+charger&qid=1567094769&s=gateway&sr=8-1-fkmr0