Might be okay. I honestly don't know. The cheapest RDS I've been impressed with was an $80 Millet that I had. Nothing fancy, but it just plain worked. To be clear...there are in fact cheapo red dot sights that can work great depending on your demands; they just might not be the uber bomb-proof, never-fail options that many of us are chasing.
I may buy one of the Bushnell TRS-25 RDS for a rifle I recently put together. It tends to get really good reviews and is a little under $100. That's where I would tend to point you if you're determined to stay under $100.
If you're willing to spend a bit more ($120-180), watch PSA for a deal on a Vortex Strikefire or Sparc. Both are outstanding. I have extensive experience with both. And honestly, I don't consider either to be inferior to my $500 EoTech XPS2.