What Do You Need to Present at Immigration With a 3 Month Single Entry Non-Immigrant B Visa?

In theory ANYONE entering thailand on any visa or extension can be asked for proof of funds, onward travel and lodging,

BUT

With that being said, people who have Non-Immigrant Type visas (O's, B's, ED's, F's RS's etc) or extensions of stays are rarely if ever asked for anything.

Just have your receipt from the consulate showing you just got the visa and you should be fine.

There is no rule that you have to show a work permit when entering on a Non-B visa (because many people who just GET a Non-B visa don't have a work permit yet :P)

I present my work permit when entering a non-b sometimes they look at it, sometimes they don't