Would my optician let me try on contacts?!

It would be hard, because of the sanitary issues involved in that. Unless you want somebody who has worn the contacts before you, and you just want to try that. That doesn't look good. Things can go wrong when you wear contacts like that from another person.
You can though, possibly request a sample, and try them on. Although, I don't know an optician that does that. It's worth a try though. I would talk to him/her about that.

They would allow you to try them on, but it would be a little weird if you didn`t buy them. Pick out a color you like and try those on only, then say i want them or i dont want them.

Most opticians have free samples that you can try. They may require you to get an eye exam first.

according to http://www.coloredcontacts.com