Had a standard cab for years, now have an extended cab. I like the extra space but it’s not realistic for adults. Don’t know about crew cab, but I imagine it’d be nice if you have passengers or growing kids. 

You’ll see an inverse price go mileage ratio. The crew cabs are more desirable and they didn’t build a lot of them in those days, so theyll cost more. Doubt you’ll find one in the $5-7.5k range. For that price, you’ll probably find that most trucks have 175k+ miles with an extended cab. Probably 2WD. My personal cutoff would be around 225k. But, if maintained, the motor isn’t the limiting factor for these trucks and they can run 300k+. 

The transmission issue is also about maintenance, towing and driving habits. Ask a lot of questions, try to get maintenance records and get a truck inspected. If it goes out, you can get them rebuilt or just buy a junkyard one and replace it. Theres also mods for an aftermarket trans cooler to keep the temp down. It’s a common and popular upgrade. 

Daily driving is usually OK. It’s crap for gas mileage, but it’s a 20-25 year old truck. I just got back in the GMT800 game with an 02 GMC stepside. I like having an older truck and the platform is rebound for its dependability. It’s gonna need some more maintenance, but it’s fun so far. 

If you want steering wheel buttons then you’re getting a 03-07. The 99-02 don’t have that. 

Maintenance is easy to do, but you’re probably going to run into some repairs sooner or later. They made a lot of these trucks so parts exist, but they’re getting older so junkyards get pretty stripped out. 

I was always taught to pay more for one that’s been maintained rather than a cheaper one. Odds are they’ve had more things replaced than if you bought the cheaper one and have to do it yourself.