and for the jack, I think that if you're a Costco Gold member, you have prolonged warranties.
If it's just seals that end up dying, 20$ for heavy duty neoprene's at Hurcules (off Brunswick) and that problem is fixed. If the rest of the jack is solid, I would buy one with a known small issue like a oil leak and bring it up to snuff. Now if the problem is a fading or chipping chrome piston, then f%^k it, stay away.
As an example, I bought a Power Fist 250 kg motorcycle lift. The thing stopping the lift from heavier weight is the undersized cylinder and pump design. 60$ for a heavy duty triple seal cylinder and 40$ for a proper cast pump and forged internals, the thing is a beast! Total cost including upgrades is 350$, I topped the table out by lifting a small tractor at 850 lbs, 386 kg. Any heavier and I have to upgrade the platform with gussets and proper 2 piece HD casters.
All that to say, if the jack is light enough, looks good and a quick raise design, not to mention low-pro. DO IT.