scubaman

Looking quickly at fat bikes on Bikesdirect, I’d say: maybe. (I ignored the 27.5+ bikes - those might also be ok, but 3” tires ain’t “fat” in my book.) I’d suggest looking at bikes with an aluminum frame and a steel or aluminum rigid fork. Fat bike tires are inherently a kind of suspension - I run my 26” x 4” tires around 6 psi, as they’re too bouncy at higher pressure - and suspension forks on cheap bikes are typically heavy and bad. I recommend against buying any bike with a high-tensile steel frame; better to buy a higher-quality bike used, and yes, a hi-ten fat bike will be an anchor.

I suggest looking for brand name drivetrain and brake components - my sense is that even the least expensive Shimano parts function pretty well these days, and I’d expect the same for Tektro. (“Pretty well” means, in particular, that they stay in adjustment, and won’t fail quickly or dangerously.)

I think it’s a plus that you’re 5’1”, because for a given bike design I expect a smaller bike with a smaller rider means less stress on the frame, wheels and components. (Big/heavy people on crummy bikes seems particularly risky.)

If you’ll need assembly help, or maintenance, from your local bike shop, maybe talk to them before you buy a bike online. They’re likely to be understanding because they may not have any bikes to sell you right now in any case. And you could - should - offer to pay them for their advice.

Anyway, I can’t imagine it’s a good idea to buy a bike from general online retailers, any more than it was ever a good idea to buy a bike from a big box store. But I’ve never looked at bikes on Amazon; and also have no personal experience with Bikesdirect, except for looking at their offerings occasionally.