To keep the cost down, just use one type of fruit to serve with the dip. You could try apple or pear slices instead – or whatever fruits are on offer or in season.
2
Slice the banana into a bowl and mash with a fork. Add the yoghurt and stir well to mix. Serve, dipping the pieces of fruit into the banana mixture.
Make the banana dip shortly before serving so it doesn't go brown.