it was the Cambodia evisa.... It just makes it easier and cheaper to have that. Back to Thailand is definitely not a problem if you have a passport with exemption privileges.
And there's scammers that try to make extra visa fees with "helping" you fill in the false paperwork. I saved a group of about ten foreigners last time.... Just say no ..
I have done it. You just have to avoid talking to the scammers that want to help you where the buses stop. Just walk right to border border. If you have prepared a evisa its easy to just turn and go back once they stamped you in at the Cambodia side