Look at the smaller Mazda SUV. They are built well and will run forever. Finding something in the $10K price range is going to be tough. The cost of the car is the cheap part. Wait till you get the insurance bill for a teenage driver.
Here is the link to the parts classified section
https://www.maverickforums.net/forums/fs-wtb-maverick-parts-products-accessories.29/
If you are on Facebook check the various Maverick group pages and UTV group pages.
If you can not find used ones check Rocky Mountain ATV as they have really good pricing on OEM parts. I believe they sell them for around $240. At least that is the price they are showing me when I login to my account.
The Can Am retractable belts work awesome. The shoulder belts tighten up when you need them too and you can feel them tighten up. When you are doing slow technical trail/rock stuff it is nice to lean forward and take a peak which these allow.
Bonus is they are pretty comfy. Only downfall is there is no easy way to add a 5th point.
I have been running them in my current Can Am. I do have a set of 5 point PRP belts that I have not installed yet. I got the PRP belts because I was not sure if the stock belts would work with my aftermarket seats.
I am probably going to sell my PRP belts.
I have the new M1 radio from rugged which is water/weatherproof. It has been solid and I like that I don't have to worry about the elements.
If you like to listen to music the PCI stuff has much better sound quality.
If you can wait until the Sand Show PCI and Rugged usually have sales.
Go on Craigslist for Las Vegas and Phoenix area. There are some listed there.
https://lasvegas.craigslist.org/snw/d/las-vegas-2021-polaris-rzr-turbo/7444257467.html
Why not pick up this Buckshot
https://classifieds.race-dezert.com/FOR-SALE:BUCKSHOT-X5R-182246
or this one
https://classifieds.race-dezert.com/FOR-SALE:Buckshot-X5-182496
My friend picked up these seats at the Sand Show. They are a little taller the HSP. His kids are 5 and 7
https://www.aces-racing.com/collections/junior-seats/products/apex-junior-seats
Can Am likes to use weird stuff. The dual phase steel might work perfectly fine if they used a thicker wall material. 2022 they allegedly went to thicker wall material, but it does not appear to be for the entire frame.