I want to get a hardcase for a Fender FA-100 Thanks

I believe the FA-100 is a standard dreadnought-sized guitar, so it shoudn't be too hard to find a good hardshell case at a decent price.

I personally like TKL cases (I have one for each of my acoustics) -- but the price of these start at around $100, which is around the price of the guitar itself I think.

Your best bet is to probably go to the store you got the guitar from and see what they have in stock. Or check Craigslist to see if anyone is selling one used.

Fender doesn't make hardshell cases for many of their acoustic models -- and I'm not really a fan of their acoustic cases in general. I ordered three separate cases for my Hellcat acoustic. Each had a problem and had to be sent back. I eventually got the TKL case which was well-built and fit perfectly.