It says to enter a valid card which is visa and errors me out. I ended up going with gyo with their single seeds so ive got a handful and freebies on the way.
Ok, been a while since I bought seedsman with a credit card, but if I remember correctly ...as you go to the credit card screen, you have to make sure you click on the picture of the visa as it defaults to Master Card. I remember one time struggling and it telling me it was invalid and I was about to throw the computer out the window and I saw the picture of the credit cards and I clicked on the "Visa" card and it went through.