Two external monitors + one own on mid-2015 13-inch entry level MacBook Pro? Is it possible to run two external monitor setup on mid-2015 13-inch entry level MacBook Pro (the one for $1299), so that laptops screen is also available? Basically making it three monitor setup - two external and one built-in.

P.S. I do not consider adding any external portable USB graphic cards, as I've tried one with good reviews and it sucked.
Yes, you can. You can use your HDMI port for one display and thunderbolt port for the other one (You may want to use an adapter for thunderbolt to HDMI). Then you go to Displays tab in Preferences , Arrangements and arrange your monitors however you want.