I could buy ceramic for 79 cents, and the best I've done on the porcelain is about $3.50.

NO, ceramic tile when new floors are required and not until then.

Another factor is the level of finish - each year we better the standard of finish based on the market demands (i.e. formica to granite, white to black appliances, VCT to ceramic, etc.).  

I prefer hardwood, ceramic tile, vinyl plank, sheet vinyl then carpet in that order.I generally don't install hardwood new because of the cost but I look for properties that already have it.

If you are planning to keep the property, you might want to consider ceramic tile.

Floating vinyl for kitchen/bath areas unless there's already ceramic tile there.Neutral colors, have done the "one color everywhere" deal but don't find it any cheaper or easier; satin or similar in kitchens & bathrooms, flat or eggshell everywhere else. 

Mistakes I made: Laying ceramic tile instead of linoleum.

Fixed roof, re-ran electrical, new electrical panel, new flooring throughout (ceramic tile and laminate), new plumbing in bathroom and kitchen, everything in kitchen new, painted.What was the outcome?

Fixed roof, re-ran electrical, new electrical panel, new flooring throughout (ceramic tile and laminate), new plumbing in bathroom and kitchen, everything in kitchen new, painted.

If the house has hardwood flooring, I would have it professionally refinished with polyurethane topcoat, ceramic tile in kitchen and bath, formica counter tops, painted cabinets if current cabinets are in good condition but if in really bad shape it can be better to tear them out and go with pre-painted white cabinets.