I paid £60 at Cranfield.
The only reason I ever go there is because IAE are the only FAA Repair Station I know of (in the south) with the kit to do the 2-yearly static test.
The most pricey must be Gatwick / Luton at around £500, most of which is the mandatory handling.
The most I ever paid was £250 or so at Tirana, Albania (LATI). £100 is common around Europe, and is OK provided one isn't going to go there again...