Car has 214k and slips like crazy.

One shop says rebuild is best. Will cost $1500.

One shop (that is also a MB salvage yard) has a similar tranny with 90k miles and says replace. Will cost $1150.

Also got a quote for a factory replacement at $3750 but seems high since got the car for under 1k. Don't want to do it.

Who do I trust? Any pros and cons? Does it matter?

I've been looking on here for a couple of days and can't seem to find the best answer. From what I've seen, tranny probs with this much mileage on these cars is not that uncommon.

I'm really ready to drive this car every day so any thoughts/advice on what do are greatly appeciated.