For basic repairs& servicing you want along the lines of...
A decent set of screwdrivers with a T20 included
A decent set of pliers, mole grips etc
A spanner set & a 11mm brake pipe spanner
A half good set of sockets with T20/T30/T40 (3/8" is best)
3/8"spark plug socket, size depending on model, or if you've got one of those extra quick clios, a 10mm for the glow plugs
Breaker bar with a 19mm (Torque wrench if need be)
Trolley Jack & Axle stands
8mm Square sump plug
Oil filter wrench
Tread depth gauge
Wire brush
I'd say for £100 you could easily get enough tools to keep your clio running. Halfords Pro on a trade card is the way forward