The buttys in Boots etc are quite cheap even airside. ryanair are as sparky says a pain on hold baggage.
I'm not sure how old Ty is, Siobhan had a seat but no allowance so we had 30 kgs for 3 of us. on teh way back we were 3kg over and they did charge. they also didn't allow pooling of weight. so each bag had to be 15 or less. i.e. 20 and 10 would have seen us charges for 5 kg.
a lot of people were clearly using all 10 kgs of their hand luggage to help with most having bags packed to teh hilt.
TBH we tend to put all creams etc in teh hold bags as it makes it a lot easier to get through security.
Make sure your socks have no holes as sometimes you have to take your shoes off!!! also belts etc all come off for teh Xray
your flight is sod all time so I wouldn't worry too much.
Oh, make sure you have sweets for Ty's ears for take off and landing to help equalise the pressure. We found Siobhan liked haribo jellys
