Walmart stores are strict and can't use it online. When in stores, you need to fill out paperwork every-time. TRU follows the same model.
Target.com, Yoyo, and Amazon have own online app process. Depending in website, you either email or upload the resale license. Stores and websites uses different policies (target.com and target stores operate like diff companies all together for this). Note for all trying to do this.
Don't just do this because you think it is a way to save money or not pay tax. Don't mess with the IRS and state governments. They will audit and prosecute you if they want. You must pay taxes quarterly. Keep records. Charge sales tax when buyers live in your state. Additionally, some posts in this thread is scaring me due to terminology. There is in such thing as a "sales tax exemption cert". How can people try to do this without even knowing the process?
Personally, I'm a licensed reseller in PA. I REGISTERED my business with the Federal, City, and State Governments. I have Account ID, resale IDs, and all the accompanying paperwork.
I also usually have 2 groups of items when checking out in stores. Personal use and work-related. People actually watch and if they don't , the IRS, city or state gov will by looking at your receipts if you are audited.
Businesses also expect a certain amount of revenue from you if you are a licensed reseller of goods. Due to my buying volume at Target.com, that is why I get some perks that others do not. Like a $44 gift card since they screwed up a $200 order of Batwings and Superman - Lex sets. Who else gives back an estimated 22% for a UPS shipping delay.
Finally, I just hope people I are trying this know what they are doing, remember, taxes are among the most common legal areas where people get prison time or heavy fines with interest. .