Lots of info on here about RSO. I'll share my thoughts. Take it or leave it. I started growing for this same purpose and eventually found it wasn't very feasible.
To make RSO you need a lot of plants. Several pounds of bud to make the full treatment. If you have never grown then producing several pounds indoors will be a big investment and a lot of learning, There is a recent thread from a guy that tried to make RSO and was very disappointed with the end result. I advise that you look up that thread.
$300 will not even come close to the investment needed in my opinion. $3000 seems closer to the mark. You will need several 1000 w lights with reflectors and electronic ballasts and quality bulbs. You will need a veg and flower room with the correct bulbs for each. You will need a large room, not a tent. You will need vortex fans, air conditioner, reflective material, pots, soil, nutrients, odds and ends, power tools etc..
To answer the question, the best quality indica seeds you can get. Northern Light is popular. White Widow I think also.
Figure 1 week for setup, 3-5 for veg 10-12 for flower, 2-3 for curing..
A better option may be to get some co2 oil right away. If you're in a medical state this stuff is really inexpensive and close to RSO. Check out POP NATURALS co2 (Honey) Oil. People will argue that this is not RSO, but I think it's a close second.