Mosin Nagants-
-Most of them have some interesting history behind them- they were used in some very important battles in WWII.
-They are cheap to buy, unlike other WWII battle implements.
-There are probably at least 50 different variations of them.
-They are fun and cheap to shoot.

My take on collecting anything- if you are collecting what is popular to collect like Winchester model 12s, Winchester lever actions, Winchester pre-64s, M1 Garands, German Mausers, etc, you will be paying top dollar for the items because everyone else wants them right now. Unless you are made of money, you will only be able to afford a small number of examples.

I collect military bolt action rifles:mausers, mosins, mannlichers, schmidt-rubins, etc. While newly imported items hit the market, they usually sell at fire sale prices, when the supplies dry up, the going prices can go up drastically, this process can take from several months to several years.