Hi - relatively new here too, but long time lurker!
My thoughts on your questions - 1) spend - how long's a piece of string? There are so many variables, age, mileage, LWB/SWB, poptop or not etc. You'll have to look at the various adverts to get a feel of what your money gets you. You will probably have seen that vans in general are going for silly money at the moment.
Pros and Cons of conversion - I guess if you buy one converted you're ready to go from the start. If you chose to get one converted you have the benefit of chosing exactly what conversion you have. This is the route we've gone because we wanted something a bit different. Doing it yourself, or having it done for you means you have control over every detail - for example we've chosen where to put USB sockets next to the seat for kids in the back, and sockets for our coolbox exactly where we want them and so on.
Timeframe might be an issue. Most converters are busy at the moment and have long wait times. If you buy a van now you might be waiting several weeks for someone to convert it, and the wait on beds is months at the moment.
I'd go and have a look at plenty of vans and get a feel of how you think you might use the space, then decide if you want the "normal" kitchen down one side, or something a bit different. Places like Platinum Wave and Camper King should have plenty of vans to look at for ideas. One top tip we were given when looking at vans - make sure you all get in the van and shut the doors. Then you'll see how much space you have on those inevitable wet days...
).
