My chain skips on the front chain rings. What do I do?
Chains stretch over time and, as they do that, they wear the chain rings and cogs to match their new size.  By the time the chain starts skipping on the chain rings, the teeth have become so badly worn that there's no alternative to replacing the chain rings, chain and rear cogs.  Unfortunately, that probably will cost $75+ in parts.

The way to avoid this in future is to replace your chain before it's stretched so much that it destroys the rest of your drivetrain.  Chains themselves aren't very expensive and replacing them is one of the running costs of a bike. You can check how worn your chain is by using a chain checker&nbsp;&ndash; you can get them more cheaply than the one I've linked to.