The weird and at the same time exciting thing with IM is that you can invest say $700 (your budget) and not make a dime from ROI, while another person can start with 0$ and make $5000 in 3 months if they will know what to do. It's all about having a plan and carrying it on until it works.
To answer your question in an honest way, if you want high-risk with high ROI potential within the day, then go for sports betting. My preference is football (soccer for the US folks).
A suggestion for today would be:
1) Open an account on Bet365
2) Bet on Levante vs. Leganes (Levante to win) and Barcelona B vs. Albacete (Barcelona B to win).
3) The total coefficients for both matches for those teams to win is 5.13. So if you bet $700, you could expect a return of $3591 (close to $5000 but within today, not 3 months, so much better for you).
4) Good luck.