What I drive: 2000 BMW 323i
My driver side rear quarter panel is damaged around the tail light, what are my options, I’ve gotten a quote from a paintless dent repair shop for $300 for a 80% job of removing the dent with no paint correction. I also got two quotes from an auto body shop for $950 and another for a couple thousand dollars.

The shop that wanted $950 said they would remove the quarter panel and have the dent reworked and then follow up with paint correction.

The shop that wanted a couple thousand dollars said the quarter panel was too compromised (according to them “too stretched for repair”) and that a whole new quarter would need to be fitted, which suggested the price to be over a thousand.

Here are images to the damage:
https://imgur.com/a/txLhi

Well, I blew up your pic.s and I can say that my local pdr guys would be sending that over to their body shop side for work. You are dealing with a lot of stretch, rust, and I can even see what appears to be some "creasing" of the metal. This is way more than a "paint correction" situation. I know it is a small area but it is a lot of work in that small area. Last guy were telling you right. l'd just shop it around for best pricing on comparable services.
Some more experienced collision guys will chime in......

So at the looks of it, I will need a new quarter panel, I see why it’s going to cost well over a thousand dollars as a new quarter panel cost around $975. I was thinking I could just search around for a used quarter panel that is a fraction of a price and just have it fitted? Plus I could search for one in the same body color or just have it repsrayed. I think that may be the more feasible option.

Easily repairable. Remove interior trim, taillight and rear bumper. If backside of the damage is accessible, use a dolly and sledge to pound out the damage, then hammer and dolly the exterior to level out the creases. If backside access is unavailable, then grind and use pullpins. Grind, fill, sand, feather, prime & block. Repaint.

Welding a new or , God forbid, used panel is much more intrusive.

$975 isn't too bad but may not include the bumper scuff.

^^ looks easy to me, tedious but easy but I do a lot of damage like that. you just have to think about were you want to move the metal. I can't see a shop replacing the compete quarter i'll bet they just cut the corner off and weld it in.
Jay D.

doesnt look in need of a whole new QP. that shop may have said that because they may not want to job. or may want it and see $$$$$$.

not sure about removing the QP and removing the dent- im not that smart but that seems like a LOT of work- more than $950 worth.

again, im not that smart, but doing like kevin and badsix say is still going to cost a bit as its tedious and time consuming. i wouldnt even think about removing the QP for that, but as stated, im not that smart. just seems a lot of useless labor and materials.

I can find used quarter panels for around $100-$300, but I’m unsure what route I should take then

can you weld? if so you could cut the damaged area out and replace it with a piece cut form a used panel. no way would I attempt to put a complete used quarter on this unless it was professionally removed from the doner car, not an easy job. and the damage doesn't warrant it.
Jay D.

I fix much worse than that all the time.
My stud welder would pull 90% of that out.
No way I would cut and weld.

I too have repaired worse, No way I would replace the whole quarter for that.
It can be worked fairly easily once Tail light is out and Bumper is removed.
I can see a Lot of shops hacking off the Quarter and replacing it for damage even as minor as this just because its faster than straitening the metal or about the same in labor once its prepped for paint.

I would think $900-$1500 would be a good ball park estimate for the repair like this to get it straitened out and prepped for paint total cost of repair depends on few different variables things like how difficult it is to remove and reinstall bumper and then the cost of Base coat, Then How old and Sun faded the current Paint is on the vehicle and how far it has to be blended in to adjacent panels to make a Perfect Paint match to the rest of the car's paint. If the car spends most of its life out doors and only gets waxed by drive through car washes and its sun faded and they have to adjust the base coat Tint to match the rest of the cars paint that drives the price up, because while its gonna match going out the door its not gonna match a few years down the road when it fades some more and there gonna be on the hook for a warranty repair.

How picky you are about not being able to tell its been repaired is gonna drive the price, So I can see it easily costing double what I quoted if you want an I cant tell its been repaired look. Prep, materials and labor for the Blend are driving the cost of the repair.

Most BMW owners I know are Very Picky and will complain about the littlest minor imperfection as they want and expect a perfect undetectable repair and I cant fault them for that. Your paying good money for a repair and if its repaired correctly it should be undetectable and last the life of the vehicle, That's the way it should be in a Perfect world, But we don't live in a Perfect world and a flawless repair is gonna cost you plenty even for a Minor repair like this.

Most experienced shops know all this up front and regardless about what you say up front about the quality of the blend you expect they are expecting a complaint or issues down the road and are pricing the job accordingly to their experience with dealing with the past issues of other similar repairs and owners.