Gotta agree with /k/anon here. Mosin is a garbage gun. They always have been, the reason they were a meme on /k/ several years ago is because they were priced appropriately at ~$80, ammo at around 30¢/rd. Not any more thanks to good ol' Obongo, but that's a whole other can of worms. I haven't seen a -used- Mosin going for less that $250 in years.>>1104862
If you're worried about it that much OP, just pick up an M&P9 Shield. It's a very compact pistol, comfortable to carry conceal IWB - It's really not even that bad to sleep with it on your person. They go for $350, but you can find them on sale for less all over the place. Takes 9mm which means you get to have fun shooting practice without breaking the bank.
If you're dead set on a rifle then get an AR-15, cheapest and most reliable option available to you at the moment.