l'm a 50+ female too and I have a Fiat Panda. It's only £30 tax and about £190 insurance fully comp, (max ncb and SE London postcode). I use it every day locally and up and down the motorway regularly. I've had it five years from new (c. 10,000 miles) and it has yet to break down. It is easy to park as it is small and has a thing that you use when parking to make the wheels more manoeuvrable. The tank costs about £40 to fill up. It's a bit boxy to look at but I'm inside it so I don't care!
The tide has finally turned against the pollution they produce, plus they are becoming increasingly expensive to maintain and in a few years time they will be impossible to sell second hand (just look at some of the recent threads on here to see what I mean).
Pussy, Blue Toff Is on here some where selling her's, other than that, be very careful with the ones at the side of the road ( No Warrantee) A pug, Fiesta / Again, take someone with you that knows a bit when buying otherwise you may come unstuck! ( Ripped Off)
There are lots of cheap little cars around, the problem is, a lot have been maintained on the cheap too. I would always look carefully at the service history, and if it's unclear, have it checked by an AA, or similar inspection.
Agree strongly with Khandro. VW Up! is being touted as an excellent small car - not surprisingly, rock solid engineering and very desirable on the second hand market