Each of these shirts is from a store called Jay Jays on the "Old Faves" line. The line features Sonic in classic style (with fake wear to the designs) as well as other video game characters who appeared in the 1990s. There may be 5 other shirts available.
The first shirt says Super Sonic 1991 (with tiny copyright underneath) The Second says "Sonic is Rad" with stars, and the last one has getting ready to run stock art with starbursts and "Bang" sound effects. The inset on the last one is the 'tag' which is actually printed into the back of the shirt. It has the store name, line name, copyright, size and the Sonic logo, making the shirts easy to recognize as the real thing.