I hope this is in the right area...
A friend over on the MLP Arena has some RB stuff to sell, but she's not sure what it's worth, so I said I'd ask here to see what you all think.
Twink Keychain clip- Great condition
Starlite Plush- Good Condition
Romeo Plushies- Several varying from good to Nearly Mint
Twink Plushies- ^Same as above
OJ or Spark- Great Condition
Tickled Pink w/ dress- Mint, unplayed with
Baby Brite w/ all clothing- Great condition
Various RB storybooks with audio tapes- General ballpark idea
Various RB VHS tapes- ^same as above
Various RB coloring books- Unused, I'm assuming... ^same as above

Thank you anyone who can help!

With the economy the way it is, prices are fluctuating rapidly in the collectibles market. The best bet for up-to-date prices: eBay. A number of the items you have mentioned are currently for sale, so you'd be able to get current market values.