Ithink its a good idea to add a shop that you can sell your guns and torsos and kits and... or trade your guns with another guy
for example: (name) (the trading thing name) (picture of trading thing) (weapon wanted)
and another example: arminrazer shark (picture) moepifier

for the cheating problem you can write a code that checks your ip and if it doesnt matched the buyers ip they can buy it

good idea

Been suggested before and rejected

1) Trading between players allows farming, which is more of a problem now than it was before. Now you can only fight a couple fights before you run out of battle points. With a trading system you could just play another account, make some money and trade whatever decent parts you get across to your main.

2) Allowing players to sell their items will mean they'll make a profit when buying item boxes. With this you can endlessly buy item boxes, so won't happen.

ok you can add an ip tracking code
and if someone wanted to give good items to their main mechs you can check the ip with the code and if it was matching they cant trade
i dont know if you can do this but i think its a good idea

This wont work either Another Computer,Latop, Ipad Think about it

If that is really the issue why not implement what many other games do, namely that you can sell any part for 50% of the buying price. Experiment with it a bit for a while and if the ratio is still too high adjust it to 40% or whatever provides the right balance.

The only issue I see is that at times being able to sell a pile of stuff would have allowed me to progress quickly. As it was I basically had to fight and lose endlessly to get enough for a key part I needed. I'd rather have the quick path but there is something to be said for earning it.

So... I'm taking it that a level restriction wouldn't work for trade. (example, a level 30 player can only trade with another level 30 player)