I am going on holiday to my parents place in the south of France

My mum says there is a mountain bike there but it needs a new shifter for the rear mech

Now this bike is probably going to be the crappest thing I will ever ride, but it's going to be better than nothing (I hope)

The info I have on the bike is very limited, so I was thinking about getting a friction type shifter as I am not 100% sure what cassette it is

Any ideas where I can get one, cheap?

Bear in mind the bike will probably be worth £20 or so

Gripshift are indexed.

You will only get a friction shifter off an old bike these days, just ring up and ask them to count how many gears there are on the back and get a cheap shifter to suit. sjscycles.co.uk are a good place to look as they stock owt from 6 speed upwards. (a 6 speed will work with a five speed freewheel if you can't find a 5 speed shifter, you may just have to drop down two then back up one to change down into 4th and fifth, but if so the indexing will work ok once in gear.)

Most of the big french supermarkets sell nearly every basic bike part found this a few years ago...

managed to damage my bike in france a few years ago and got a new mech for next to nothing 

My Mum doesn't live there, it's just for holidays

Also the info from my Mum and her partner is open to interpretation  

It will probably have Sturmey Archer on it or something!

I have found something on SJS which is a 6 speed, but also switchable to friction - £6.99

Bike will be worth twice as much now