Yes, the software can be priced differently at retail (online) stores or based on time of year.  Also, please note that what is offered at Costco is TurboTax CD/Download/Desktop version not TurboTax Online.  You can purchase the TurboTax software where you choose.  Some retailers offer bundled packages that include the state preparation program.  Depending on the time of year and marketing plans, prices at turbotax.com can fluctuate.

https://ttlc.intuit.com/replies/3301381