Hmmm, $43 pump, free shipping, fills to 4500 psi?

Got a friend with a small pest problem, he's been buying nitro piston and gamo and the like that shoots 1300fps, etc, only he can't hit anything with them. So I suggested a marauder, maybe the new gauntlet or storm rider, but that he would have to pony up for a pump too, and they cost a couple hundred bucks. Well, he comes by the next day says he's going to buy a storm rider for $200. I ask how he plans to fill it with air, and he tells me he went on eBay and found a 4500 psi pump for $43!! And sure enough, there are a bunch in the $40-$50 range, with free shipping no less;

https://www.ebay.com/itm/PCP-Airgun-High-Pressure-Hand-Pump-31mpa-310bar-4500psi-for-Air-Rifle-US-Seller/173020018220?epid=730639014&hash=item2848cbf62c:g:6BAAAOSwXLZZqL9n

Any body have experience with these. Heck, I'm tempted myself at that price and I really don't even want or need one.