200$ USD is certainly not a lot, but you can also start with them in twitter.
I recommend such a plan - and I would also stick to it.
I would buy Twitter Ads accounts with a credit limit of 200$ USD.
For your budget they can be bought pcs 5-10 depending on where and what quality, but good pcs 5-7.
Under this plan you get 5-7 Twitter Ads accounts for 200$, on which you can advertise your SaaS project for 1000-1400$.
Customize Event, Lead for your SaaS project, run ads for 10-30$ to see what creatives give the best performance and so on.
Try this plan, if you need help with this, I am actively involved in Twitter Ads, contact me and I will give you my contact Telegram