By Cameron Huddleston, Former Online Editor September 25, 2009 Using coupons is a great way to save money -- that is, if you have time to clip them or search for them on the Web. But a lot of us don't, or we accidentally leave the coupons at home when we go to the store. That's what makes Coupon Sherpa, a relatively new iPhone and iPod Touch application, appealing.Launched in March by Luke Knowles, the free app -- yes, FREE -- lets you download in-store coupons for retailers, restaurants and services. You can search by store or category, and the coupons appear as barcodes on your iPod or iPhone screen. Some reviewers of the app complain that the codes don't always scan. Knowles says they work only at stores with optical barcode scanners (most still don't use this technology), but the cashier can type in the code. Besides, he adds, a lot of printable coupons don't scan either.Most days, Coupon Sherpa has at least 100 coupons from well-known stores that you could find in any major city. And some of the coupons are exclusive to Coupon Sherpa. Unfortunately, it doesn't have grocery coupons -- but that's because the technology isn't there yet from the manufacturers, which want the paper trail of print coupons, Knowles says. However, Coupon Sherpa now has a Web site (launched the beginning of September) that has hundreds of grocery coupons -- as well as coupon codes for online retailers and printable coupons.A couple other mobile coupon apps you might want to check out: MobiQpons and Yowza.