Shoplifting is covered by 720 ILCS 5/16-25 in Illinois. If you are trying to take any item out of the store without paying for it or trying to change the price tags with the intention to buy it at lower prices, then it is considered theft retail in Illinois.
Penalties
Small-time Theft: Items under $300 are prosecuted as Class A sin or crime, which could include:
Felony Theft: A Class 3 felony can be charged for theft if the value exceeds $300, with a sentence of two to five years in jail.
Additionally, Illinois includes provisions for repeat offenders that can result in far harsher punishments.