In long: (all IMO)
On size, 18" is the go-to size of cymbals. 16" is good too, but sound better with a brighter product line. The gamut of 14"- 20" is best reserved for drumline and marching band. I use these sizes for color variation and to better suit the varying bodies and strengths of our kids.
On brand, Zildjian will be the best. Sabian is fine, but I have only really liked the Synergy product line. Meinl...for marching band, and only if it's your only option.
On dark/light, look at the thickness of the cymbal. Thinner=brighter, thicker=darker. Zildjian uses product names to help you: French=light and bright, Viennese=general and dark, Germanic=hella heavy and hella dark.
On cost: don't think about it. Ask yourself instead, do I want quality? This is especially important if you don't know what to shop for.
On crash or suspended: consider a gooseneck cymbal stand. It will allow you to use your crash cymbals as a suspended cymbal without needing to remove the strap.
More advice: optimal cymbal tone is a life's journey. Sometimes a dirty cymbal sounds better. Some people bury their cymbals in the ground for a few months to change the tone. They will sound different even within the same product line. They will sound different on stage vs your rehearsal space vs wherever you go to try them before you buy them. Good luck!