Hi Matt, welcome to the Forum! You are sure to be on the receiving end of lots of helpful advice here, as I have found.
Can I offer a bit of advice? You say you're on a tight budget - me too. I was fortunate to have enough money in my savings account to buy a caravan from a dealer, in good condition for its age. (It's 16 years old!) The problem now is jiggling my budget around so that I can actually get out and use it! It really is a lesson in deciding on your priorities in life. If you can go to a dealer, all the better, as the law insists they sell items that are 'suitable for purpose', and usually offer a short warranty even on an old 'van. You haven't got much come-back if you buy from a private owner. There are so many things that can be troublesome in a used 'van for the inexperienced buyer.
Having said that, you can save lots of money by buying all the accessories needed from a car boot sale, or E-Bay or other on-line sales sites, and it's very exciting gathering all the necessaries ready for your first outing!
Don't be afraid to post any question on the site, I repeat, there's a wealth of friendly and helpful information to be had on this Forum. The more research you do in the early stages the less chance there is of coming unstuck. I wish you happy times ahead!