Quick question about junk silver.

I've got around 6 or 7 ounces of rounds that I want to let go for some junk silver. I know its a "if you want it, do it" type scenario.

My question is what is the best way to go about trying to do this? I'm new to Pmsforsale and I have 0 clue how it works. I'm overwhelmed when I get on there. I have 0 local coin shops within a 100 mile radius. The only thing I have are peddlar/antique/flea markets where the sellers think a 1964 quarter is worth 20 dollars. Until you bring them one you want to sale and they offer you 3.

I've also been looking at the sdbullion BU quarters/dimes. Are they worth the premium or am I better off getting the circulated coins? I didn't think I'd be interested in junk silver when starting this stacking. Then I bought 6 quarters off a friend and now it's all I'm looking for lol. Thanks in advance for the help!