CT wrote:
Last year, birds ate all my sweetcorn before it had a chance to grow
and ripen. What are some inexpensive ways to prevent or repel birds
from eating my corn and other vegetables?

I use fleece for seeds and netting for fruit/veg that's a bit more
grown up. Try eBay for cheapness.

I throw netting (the more robust stuff, then reuse it each year, rather than
the pea netting, which rips) over fruit.

Never had birds eat sweetcorn before. You sure it's not rats? (OP, not CT)