Entry level riders can get in cheap as far as entry fees. They just do not get much chance to win much money back until they get into the bigger 'added money' events.
The added money event is a two edged sword. When you get to the level to win some of that money back, it knocks you out of the easier 'lower level' classes because you HAVE won money. Either way, the entry level classes are a lot les expensive to get into. What you do run into are entry level reiners with a lot of money that compete on $100,000.00 horses.