staples had some cheap dells a few weeks ago i5s under $400, slap a $150 gpu in and you would be set. If you are going to buy something cheap and prebuilt you should actually wait for a deal that doesn't suck too bad. The one you have shown really isn't very good for the price. I would just look for a cheap i5 w/o a gpu, make sure the PSU is ok inside it and buy something like that. don't settle for junk "gaming" cheap prebuilds like that, if you are going to buy cheap junk then buy cheap junk no gpu and upgrade the gpu and psu if it does not come with enough power. you will get better processor/ram specs (where it really matters) and actually get to choose a gpu that is decent on top of it, instead of getting stuck with shit everything.
and i don't want to plug newegg or anything but if you are gaming on a budget and have a steady income, you can always try to sign up for a newegg preferred account. that way you can buy the whole pc now and pay it off as you go. I think they have promos with no payments for 6-12 months if you spend like 250-500 if that is you cup of tea.
Again just don't settle for shit with a good price tag, cause it will still be shit.