Do NOT buy bath toys. I know we all get sucked into the cute ones we see in the store and such. But one thing I have learned is that my kids never really played with those. Their favorites were Mcdonalds toys or random pieces from toy sets.
I also hated the fact I had to clean them and keep soap scum off them.
So here's what you do. When you are sorting toy bins and you have random pieces...throw them in the bath for a week or 2 and then toss them. Same with toys from kids meals. I throw them in the trash a day or 2 later but now I give them a few days in the bath.
Saves money and also uses up those random toys.