You can find some cheaper ones online, but you’ll get what you pay for. I usually argue for buying a higher-quality set. F.C. Ziegler has some chasubles starting under $100.00.
It’s important to recognize how lesser quality will play into everything. Firstly, they’ll likely be less appealing. They’ll wear out much faster. The polyester will make Fr. sweat quite a bit.
A good middle ground is making your own vestments. You can get a full set of patterns online for $50-100, and none of them are that difficult. The hardest part will be finding a good fabric, but some sites that sell patterns will also sell fabric.
In my opinion, low price and high quality won’t really go together.
If I may ask, who or what are you purchasing for? Are you purchasing for a newly ordained priest, or for a parish?