This was an issue I'm facing. I have a few extra things I need to get back to the US. I was going to ship them but the shipping would cost about half of the value of the items.
So, I plan to get them into my suitcase somehow. I have three flights home. I will check my bag on the first one because it is a turboprop and can't handle a normal full size carry on.
But the next two--one across the Atlantic and the other a domestic US flight--are the questionable ones. I have never checked bags on them. If I can close my suitcase, I will do carry on. (No weight limit). But if I must "expand" the suitcase I'll have to check it. Luckily, a checked bag is included in each fare.
I have shipped items back to the US in the past. It is not cheap.
But the question that has not been asked is.....will you have to carry these items around your entire trip? Do you want to? If not, ship them home. If the merchant is honest, and they offer shipping services, then they are usually reliable. I've purchased items from major department stores and had them ship it. I've never had a problem. Not sure about small retailers.