As others have said, almost all laptop and phone chargers will support 100-250V at 50 or 60Hz. They have switch mode power supplies, which for various technical reasons I won't go into, are very easy to build to support all the world's major domestic voltage and frequency standards, so almost all of them are built as such. Check on the chargers themselves to be sure. It's also quite likely your shaver will support this; again, check on it to be sure. If this is the case, a travel adaptor would be sufficient, converting the shape of the plug only.
However, a word of warning. I would also suggest buying from a reputable retailer in your home country (maybe an online one), and not from a site like Amazon or eBay where a huge variety of companies can sell things claiming to be other things with limited policing, and where fakes are common. Sure, in all likelihood there won't be a problem, but I wouldn't want to be putting myself in danger of electrocution or fire, which are both certainly possibilities based on the horrific adaptors I've seen in the past. On the other hand, things bought in reputable retail stores or from the websites thereof are generally quite good at complying with all relevant electrical safety regulations. Even if it costs a bit more, to me this is worth the peace of mind.
On a similar note, buy one that is solely designed to convert US sockets for EU plugs. These tend to be a lot more sturdy and safe than the ones designed to convert anything to anything.