World of Van Helsing: Deathtrap

You will get this over time or you can grind it out in under 2 minutes on any mission. Before you start a wave, walk over to a ground trap and click to open the menu and build a trap with and sell it with . Repeat 249 more times to get this achievement. If you do this in before a wave then nobody will attack you plus it sells for the same amount it cost to build it as long as you dont upgrade it.
I went to an empty trap and spammed , , , , , and repeat in that order 248 more times

For this achievement you simply have to buy 250 ground traps and lucky for you when you fist spawn into the map when you buy a trap you can sell it for the same price so it's a simple case of spamming lt a and x in that order while standing next to a ground trap, you should pick up your achievement in about 2 and a half minutes

If you would like a video guide for this I will leave my guide below