Officially you can (come july) give up to one ounce to someone for no financial reimbursement (I suspect bartering might pass the sniff test though), medicinally technically you can get reimbursed for your expenses. But people just use that as an excuse to charge 125+ an ounce (how someone could justify that said 1 ounce costs them $125 to grow is beyond me, but it seems to work as their sheild.)
Note that's all technically, in reality, in oregon you're not supposed to sell pot, you can gift it (come july) to anyone over 21, but selling it is a no no, and oregon has some stiff laws if they want to bring them out. (It's an odd state, but I like it... even if the politicians aren't currently listening to the text of the legalization measure that mentions many times it's not to have any effect on the medical program.)