I've never had an issue with any sellers...the ones who are running a business either in China or the stateside shipping locations for China goods.
If you bought 0 to say 30 VDC adjustable plug in the wall supplies, how many amps do you need per supply. There are quite a few at 3 amps output for around $35 shipped. Anything else is pretty much something that you have to at least mount on a board and wire up.
How many and what output do you need?