There is no Customs duty on personal items. The Customs agents won't even bat an eye unless you have several bottles of liqour, tons of truly expensive jewlery, or brand new electronics. After all, the FSU is not known for the illegal import of drugs or other items (except for too many bottles of vodka).
When I arrived with my (then) fiance and son, we had 9+ bags - 6 suitcases each nearly 70 lb, 3 carry on bags, plus my laptop and her large pocketbook. These were the items I was wrangling. She carried the 5 y.o.

I still say the best $20 I've ever spent was the tip I gave to the skycap, who brought over a large luggage cart, and found us a minivan taxi!