i've bid over 1 billion on gear before today it's hillarious you get these hardcore iranians that think 250million is alot and i just smash whatever they bid. Basically your right supposedly the bank holds 175 so you spend all you on any item you feel won't be bidded on usually i go for a level 1 item so it doesnt tempt interest then bid all your money collect whatever you have inside the stadium providing nobody comes close to the amount you have put on you get all the money back + what you collected from your stadium.
For example atm i've got 1.3billion I bid 1.3billion on any item of sports gear i feel wont be bidded on i usullaly wait till near end of season too where less people are interested in the level 1 items , so i put down my 1.3billion. My money will end up at £0 but i then collect from inside the stadium sending my bank up. and as long as nobody bids too high the money will add onto whatever i've collected from inside my stadium.
Say you do put down 200 million and nearest person bids 20million you will get the item at under 20million depending on your level of sports shop but it's very easy to exceed your bank i'll send you a screenshot of my money buddy