Welcome to the forum, overall we have a pretty great community here and in game. If you're like most of us around here you might get hooked pretty quick. If you ever have any questions about unit prices the best way to find out is to ask here on the forum, the veteran players here are reliable. http://www.fantasicaunofficial.com/t6109-price-check-trade-advice-thread
On a side note, beware there are scammers out there...some people claim they want to album and others say they want to level break units etc. Just be careful out there.
You won't be able to do any trading until you reach level 31. Right now focus on leveling up some 4*s, like Helmut
The best deal I've found is a set of 5 new 4*s for 2 te.
Last but not least, when I was first starting I found this guide to be incredibly helpful