It's the best time of year to go shopping for back-to-school needs. Missouri and Iowa stores are stocking up now for the first weekend in August when many items are exempt from sales tax.

Missouri's tax-fee weekend is Friday Aug. 3 through Sunday Aug. 5. Iowa's is just two days, Aug. 3 and 4. Illinois shoppers will have to have to cross state lines because Illinois does not participate.

In fact, Iowa may be the best state to shop for sales-free deals. The entire state participates, whereas many Missouri cities opt out. Iowa has a broad range of what makes the exempt list. You can buy the standard tax free clothes, shoes and school supplies, but did you know you can score tax-free diapers. That's right both baby and adult diapers, even bibs and blankets. Also on the exempt list: choir robes, chef's uniforms, garters, corsets and rubber pants (?!). Find the complete list of eligible purchases here.

Missouri's tax exemptions are much more restricted. They're limited to clothes, computers and school supplies. The real hitch is watching where you shop. In our area, Shelby and Pike Counties have opted not to participate. Certain cities have also declined to take part, including Palmyra, Canton, Paris and Vandalia in our area. Click here to find the complete list.