Thanks all for your replies.
Originally Posted by
beamac
Globalesim will provide you with add on option of UK/US orCA mobile number
I used them before and it work very well, but since approx. last June they still have some problems and the voice&messages services is not working. They even publish it on their website that they are experiencing *temporary* issues in the US and the voice&messages services is not working (data works well). The skype/whatsapp is not an option for me because I need the US number for receiving sms messages + receiving phone calls
Originally Posted by
gfunkdave
Mint is the way to go.
Do they provide prepaid one-time only eSim without any contract? Can I buy it online? I was trying to find it on their website but there are only monthly plans.
Originally Posted by
paperwastage
most are monthly ... how long do you need the number for?
Exactly

I needed just for about 15 days and that is it.
Originally Posted by
der_saeufer
If you have an iPhone, you can use the T-Mobile test drive app to get 30 days free. You do need to be in the U.S. or VPN there to set it up, but you don't need to pay. Download the app in advance and set it up on the wifi at your arrival airport.
I have an iPhone and checked the app and it is no longer available, but they have a new version of that, but it is not available in my country App Store

I do not have US app store account and do not want go through that troubles just for that.