They no longer hold up my rear hatch. 2003 MCS with 67K miles. It hurts the noggin!!! Any ideas on how much to fix?

 

Auto parts stores have replacement lift supports in many sizes. Not sure if there is any thing special about the MINI's, but that is where I would look first. They are somewhere between $10-15 IIRC.

 

You may want to check to see if it is only one or both.
Had one strut go out on our mini-van and the hatch would drop like a rock. Replaced just the bad one and everything back to normal. They have the struts just so that with one bad the other is not nearly strong enough.