Sports bra suggestions?

ENELL sports bra.  It's not pretty, but it keeps things in place. 

You can get them online at Title Nine and Ladies Only Sports.

I don't know what you consider expensive, but I can't say enough good things about the Lululemon "The Bust Stops Here" model which I think is in the $55-60 range. It's the only sportsbra ever that immobilized the bounce without creating uniboob (though now I am  a uniboob!) They make various bras all the way from hot yoga flimsy things to this one. (It's not the same as the Ta-Ta Tamer, which didn't tame mine.) This is the only model that does the job for me.

If you get the right size, it will fit snugly against your chest between the boobs as well as around the band, so that you don't get chafing or one boob jostling the other, and there's fabric to wick the sweat as well.

None of the "Champion" type brands did anything for me. I had a decent run with a Brooks model that was not very stretchy, but even if it wasn't discontinued, I don't think I could use it now as it had underwire, and was semi-pullover. I think it was more expensive than this one anyway. I tried a couple models from Moving Comfort. One of them gave me a uniboob and miserable chafing, so I went to see the rep at a marathon expo. She put me in a C and just squashed the buggers flat (and they still bounced!). I fit the DD in Lulu perfectly, no bounce, no chafing. The secret is a panel of non-stretchable fabric that runs across the upper part of the cups, and it stopped my jiggle without squashing. 

For the same reason you posted, I wore it as a daily bra after the lumpectomy for quite a while, and post mastectomy until I got the surgical bra. I still wear it running, sometimes with a beanie foob, sometimes none, because the structure supports each breast independently.

I also like that it comes in a range of colours that aren't just "jocky" looking. I have a purple one - goes with everything ;-)