With money that tight... well, let me backtrack, then. You say in your OP that you've done more than a bit of art. The layer approach requires good drawing -- if you draw well, and if your acrylic experience has given you a lot of brush time, then why not start with that?
Search here for demos by wfmartin, Bill Martin, who is a master at the grisaille - color glazing technique. The search function in the forum is not so hot -- try the "site" keyword in google... demo wfmartin site:www.wetcanvas.com
Meanwhile... I am terminally cheap, a founding member of Team Cheap, so read on.
Traditional cleaning would be with odorless mineral spirits. Artist's turpentine is expensive and toxic. OMS from a home improvement store is cheap. It will be (possibly) slightly less refined than artist's OMS, which is too expensive for what it is. Don't breathe its vapors any more than you have to.
Alternately, and non-toxically, you can clean in supermarket safflower oil following by gentle soap-and-water. I would use whichever Dawn product is used for oil spill remediation... sorry, I don't know which that is and my supermarket has 5-6 different Dawn formulations.
Let the brush dry thoroughly before using with oils again.
If you're in the US and further, if you're near a Michael's or A.C. Moore, sign up for email coupons from them. At least once a month, each one issues a 50% off coupon. Moore even recently had a 55% off coupon. Each chain honors the coupons of the other here in Massachusetts.
The ultimate Team Cheap palette is 4 colors, the European primary colors: "cyan" (more on that in a second), magenta, lemon yellow and white. These will mix into any color you want. Most European color brands have these primaries. Jerry's Artarama sells several low-cost lines that are regularly on sale. My own choice is Lukas Berlin water-mixable paints, when on sale, under $3 for 37 ml (plus shipping & handling).
HOWEVER, cyan is a special case. Most European brands sell a tube marked "cyan" or "primary blue," but it is phthalocyanine blue PB15:3 plus white. This makes dark colors impossible. You really want just plain phthalocyanine blue PB15:3. It is a VERY STRONG, staining pigment. A 36 ml tube lasts a LONG time. The strength of the pigment is why the brands add white, to prevent school kids from mixing disaster.
For painting supports you can use (in order of increasing cost) "gesso" coated paper or shirt cardboard; "gessoed" hardboard (Masonite); pre-primed canvas pads; pre-primed cheap stretched canvas. In place of artist's gesso, you can use so-called latex house paint. It's actually acrylic paint, and most gessoes are acrylics. Flat (matte) is much better than glossy or semi-gloss.
Again, if you're in the US, sign up for your local Freecycle and use the WANTED function to get free house paint... sometimes even canvases and other art materials. At the same time, monitor the group for any OFFERs of things you need, not just art supplies. http://www.freecycle.org/
It can be frustrating, since you have to act instantly on high-value OFFERs or you miss out.
For brushes, Jerry's Artarama has a mega paint and brush sale once a month. Again, sign up for email notification. The house brand Creative Mark Pro Stroke Premium White Bristle and the same brand's Pro Stroke Powercryl brushes are actually quite nice. A set of 5 of the former on sale is under $8, the latter under $10, plus S&H.
Powercryls go to a sharper knife edge, but are not as stiff as the bristles. Just get flats and possibly one set of rounds if you're going to paint small details. The flats soon wear into filberts.