Can you switch crew skills in star wars the old republic without losing experience in the other skill?

I am a low-level light side cyborg smuggler (gunslinger) that specializes in cybertech, scavenging, and underworld trading. I am thinking about switching my underworld trading to investigation to get schematics and possibly switch cybertech for armstech. Will I lose my accrued experience in my previous skills? Also, are these the best strategy for me? How can I reset my advanced skill tree? And where can I buy materials besides the galactic market? The prices are outrageous. 30,000 credits for 10 entry level materials is highway robbery.

Thanks for the help.