Saw this earlier and had to jump in because I was in your shoes last semester. Honestly i been using Google NotebookLM AI Research Tool for my own research projects lately and im pretty satisfied with how it handles the hallucination issue. Since you are on a budget its basically free right now which is the best price for a student lol. It pretty much treats your PDFs as the only source of truth so it wont just make up random marine biology facts that arent in your text. I was super happy when I realized it generates citations you can actually click to verify the context immediately. If you want something a bit more specialized for science papers tho i really like Elicit Plus 12000 Credits. It costs way less than 30 bucks and is great for getting through thirty PDFs by Friday. I used it for some environmental data analysis and it was great at extracting specific methodology details without the fluff. Just a tip... try to batch your uploads so you dont waste time. Scientific papers get super dense and these tools really save your sanity when you have a deadline breathing down your neck. I havent had any complaints using these for my own technical docs and they definitely stay within that budget you mentioned. Youll be fine, just take it one paper at a time...

To add to the point above: I was pretty stressed about hallucinations when I was processing deep-sea thermal vent data last month. I have been super satisfied with Humata AI Pro Subscription because it highlights the exact technical sentence in the PDF for every claim. It handles 60-page docs for 14.99 a month and honestly hasnt failed me yet. No complaints, it stays grounded to the source text.

In my experience, you really want something that stays grounded in the actual PDF text so you dont get those hallucinations your advisor will catch. Ive tried many tools over the years and general AI can be sketchy with technical marine biology terms if it isnt forced to look at the source text directly. Since youre looking to stay under 30 bucks, these are my go-to recommendations:

• SciSpace Premium Academic Plan is basically built for this. It has a specialized copilot for about 20 dollars a month that handles citations way better than Claude.
• Google NotebookLM Free Edition is honestly amazing since it is totally free. It creates a grounded notebook based only on your specific uploads.
• Perplexity Pro Monthly Subscription is 20 bucks and lets you toggle between different models to verify facts. NotebookLM is probably your best bet to save money while keeping the data accurate. Good luck with the thesis!

Seconded!