Some starting questions

[jaber123]

Alright, so im wondering if i write tracks on card with mag stripe and IC, and leave the chip blank, try to buy something in store, and if the seller tries to put chip into POS, it gets an error or something, do they try mag stripe by default or do they raise alert and start asking questions insted? And what merchandise would be best to buy under $15 with the card from wich i could get money later on? Thanks upfront.