They start at $22 US and there is postage and tax to add to the cost if you are outside of the US. These are the first pterosaur related T-shirts that I have been satisfied with and they come in a variety of colours and designs.
The T-shirt shown cost a total of $30.96 to be shipped to the UK. This was a total of £22.56 at the then current exchange rate and took 12 days to arrive on my doorstep.
(If in doubt, go one size larger than expected)