"I've heard that some tile can be installed right over linoleum. True? " Frankly, the book says no. The only resilient sheet products that can be installed over are those that do not have a 'cushioning foam layer' sandwiched in the construction.

Research the internet for good information about the differences between ceramic and porcelain tile.

All tile is ceramic, but all ceramic isn't porcelain. Porcelain is simply fired at a higher temperature, making it stronger.

Actually either one is fine for flooring.

Impossible to give a price with the info we have. Is the house on slab or post & beam.? If the latter, you may require strengthening the floor with additional plywood, how easy will it be to remove the vinyl you have now? If slab, how flat is it? Does it require work to obtain a proper surface, etc? Geographic area plays a part also on pricing.

Kinda like saying, "I want some work done on my car...how much will it cost?"

Look for a through body porcelain. It is a stronger tile and if it does chip, the color goes all the way through so is not as noticeable.

I would not install tile over vinyl. It needs to go down over a clean, level, flat surface. Any residual glue from previous flooring must be scraped off a slab subfloor. Spray the floor with water where the glue was to make sure the slab is absorbent and the water does not just puddle up on the surface (glue in pores).