Lessee - I've been buying accessories lately, and these are the prices I have paid, or would pay for these items...
Sippy Cup - I wouldn't pay more than $5.
peach or yellow? toothpaste ($7?) This price is fair, if there is no damage, no fading.
xylophone ($7?) - I would not pay more than $2 for a standard colored xylophone. The fancier ones go for more though.
Aqua and white dish ($2?), yellow spoon ($2?), pink trimmed bottle ($1?) and duck comb ($2?) for Baby Lickety Split - You might get more for the bottle if it is not yellowed or faded. The spoon seems right. The dish you might get a smidge more for, again, if it is not yellowed.
First tooth stacking toy - pink base . . . it's missing the smallest piece at the top ($5?) I just paid $3.50 for a complete stack toy.
Pink teething ring for Baby Lickety Split ($8?) - This is about right.
Star panties ($2??) - Hmmmm. Between $2-$5 I'd say. I don't buy these, so I haven't been watching for them.