I'm looking for a bit of advice from you guys. My 10yr old stepson is dying to ride with Dad. Money was pretty tight up until recently so I myself couldn't even get out more than once so far

But anyways, it looks like we'll be able to get out a couple times this year and more than likely about once a week next season with a several day trip to Breck if all goes well. Rather than just letting him rent the pos stuff they have at our local place the wife and I decided it'd be better in the long run for learning and costs to just get him the stuff he needs. I haven't done any shopping or looking around yet. He's 65lbs currently and about 4'5" or so. I THINK a 115cm board should be a good start but I don't know if I should go shorter so it's easier on him or not? Can anyone recommend some brands to look for/stay away from? I obviously don't want to blow 300 on a deck for him to learn on but I don't want to get stuck with a crap setup.
Thanks for any and all help guys!