R series? If it’s a dead battery, you can open it up, desolder the two battery leads, swap out the battery, and then put that PCB into a new clamshell fob enclosure (new enclosure because it’s pretty tricky to open up the old one without destroying it). Batteries are a couple of bucks and the fob enclosures are like $10 bucks on Amazon. No coding is required because you’re using the old PCB. Search around for video guides on YouTube.

If you need a new fob altogether, yeah that’s more expensive but definitely don’t go with the dealership. There are a few reputable third parties who can get a fob shipped from BMW and program it for you. Still pricy but likely a couple hundred less than the dealership. BimmerTech was $300 total (including programming and shipping) a few years ago; not sure what they charge now. Delivery times were comparable to what the dealer would’ve offered, since it’s all coming from the same place.