When you are starting out, or even if you are quite experienced at fishing, there really is no need to spend a fortune on fishing reels. These days even quite inexpensive reels are very well made, work well and are robust enough to last for many seasons.
If you are intending to buy more than one rod so you can have a float and leger rod set up at the same time, buy two reels otherwise one will do. You should also try to get a reel that has a spare spool so you can be equipped to fish with different strengths of line to suit different venues.
For the beginner, and for most general pleasure anglers, the fixed spool type of reel is the only type you need. Good examples of these are available from £10 and if you can afford a reel of £20 or more it will serve you well for many seasons. If you stick to reels made by the established manufacturers you should find that any model in their medium price range will be fine.