I am looking at building a hot tub out of a stock tank.  I'm going to be moving somewhere for just a few years, the house doesn't have a good soaking tub, but even an entry level hot tub from Costco that can fit 5+ people is ~$4K these days.

It looks like I can get an 8' stock pool for about $500, then add a pool pump (~$100), pool filter (~$150), and 11 KW spa heater (~$450) to make a hot tub for about $1,200. It won't be jetted but I could add those later (looks like spa conversion kits are ~$500 on up).  I've got decent DIY skills for plumbing and electrical.  I'd have an electrician wire a sub panel for 240v service with GFCI breakers to run the heater.

I think I can just put in a gravel pad for it to sit on, and trim some poly iso foam board insulation to sit underneath.  For another ~$200 or so I can get a 2' tall insulated tarp with an inch of closed cell foam to wrap around the thing for more insulation.  A regular spa/pool cover should help with heating in the winter.  If that doesn't keep up I could build a wood enclosure around it to put more insulation in.

I'm a little torn between a metal and plastic tank.  Plastic looks like it has nicely sloped sides (more comfortable) and with 1-2" thick of plastic there's some insulation value there vs. a thin metal tank.  Metal looks more durable but I'd probably have to either put some sort of coating inside or a pool liner (few hundred bucks and some work) to protect it and prevent rusting.    Both are about the same price.

I am also not sure if the gravel base + foam board will be sufficient or if I should spring for an EzPad ($550).  Given that its a few hundred buck stock tank I think the EZPad is probably overkill.

I'd be trying it in a climate where the weather gets down below freezing in the winter, hopefully a bit of insulation plus a 11 KW heater can keep up.  I can't imagine a cheap entry level jacuzzi tub has much more insulation that 2" of plastic and 1" of closed cell foam anyways.

Anyone tried this?

Go to youtube,type in diy hot tub,lots of great ideas.

You can get a used hot tub for $1k or less.  Seems like less work.

This^^^

Depending on what it needs sometimes even cheaper. I have one I'd give you. Last I checked the pump and heater work but the lines leak and it's hard to fix them...it's just in my way...

Yep, resale on hot tubs is low.

A few years ago I tried to give one away, had no takers so it got cut up and used for fill.

buy an inflatable one.   They're great  n300-400 range

Update:

I was ready to go get a real hot tub ordered from Costco or used after the last round of inputs, but figured I'd scope out the electrical prep first.

I thought it would be easy to run a new subpanel to our back deck at the new house.  At my current place I had a subpanel with 240v, a 30a circuit, flood lights and a 20a circuit run for a few hundred bucks.

Not sure if it's the new location, the economy, LGB!, Or some combo thereof but of over a dozen electricians only one has even given me an estimate and it came in at over $5k for a subpanel, 240v GFCI, and some 20a outlets.  Even dropping the 240 down to a 120 30 amp isn't dropping price much.

I'd feel ok doing the electrical downstream of the subpanel myself but I don't want to run the wire from the main panel DIY.

$5k is just too much for this job.  We do have a basic 15 amp circuit out back but it's inconveniently placed, so I'm either thinking (a) inflatable hot tub or (b) stock tank pool with propane for heat and a pump that runs off battery most of the time (extension cord/solar to charge) so I can place it where I want it.

Still trying to get a more realistic electric quote but may end up on plan B.

What about letting your local tech school wire it? They used to do stuff like that down here for a reasonable price. All the pool people include wiring in the install. And sometimes the technicians do side jobs if they installed the old tub. So check with the original owner and see who was the installer.

Plastic stock tanks are cheaper and seem to last better for me.https://www.tractorsupply.com/tsc/catalog/livestock-waterers-tanks