I think a good first step is to make a firm decision about how you should progress in this hobby within your budget. You have the Syma. Have you mastered it completely? Have you finished the scratch build you mentioned earlier?
*When* you're ready for indoor flight, the night vapor requires a room about 20x20' to fly well. I can barely fly a figure 8 pattern in my 20x20x8' finished garage without going into high alpha -- any smaller and you'll have to fly it like a helicopter to change directions.
PZ lists the minium size for the mini-vapor at 15x15' - I can't confirm this, but it is lighter and has a MUCH slower prop, so it's possible. there are a few living-room-flyers on the market, but many haven't been kept up to date and can be more expensive that medium sized outdoor flyers. If you can go to a small gym size or better, the indoor flyer market picks up quite a few nice inexpensive options.