Mission speakers are pretty nice for the price. You may want to look for JBL & Infinity speakers, too. They make pretty good speakers, they're big names & sell a lot of speakers, and they change models frequently. These factors usually mean a lot of speakers on Ebay to chose from, and a large supply means low prices. Models from the late 90s often sell for $.10-$20 on the dollar (before shipping).
Just try to buy from someone with good feedback, and investigate the condition of the speakers. I'd personally avoid speakers older than 10 years with foam surrounds. Almost every speaker I've ever seen with foam surrounds that's over 20 yrs old has the foam rotted out. The longevity depends a lot on where the speakers were used. Very humid parts of the country will rot the foam a lot faster.
Pay close attention to the shipping. Since Ebay charges a fee based on the final value, one trick sellers will resort to is charging very high shipping to avoid paying final value fee. And often people don't check the shipping cost before they bid only to be surprised by charges that are two or three times what it really costs to ship. Your better sellers don't resort to dishonest tactics like this (again, check the feedback).
I've bought and sold on Ebay with no problems, but it comes down to the individuals involved. I treat people fairly and trust in their feedback, and so far it's worked for me.
Again, the Athena's at BB are pretty good for the price, and you wouldn't go wrong. But for $200 you'll probably get more used.
What do you plan to drive them with? That is, what kind of amp/receiver? How much power? How large is your room & how loud do you listen? And what kind of music do you prefer? Those questions can allow people to tailor their advice a bit more specifically.
