Does a 3G phone do the same thing as the dongle? On the same sort of price plan? Could I connect it to my laptop? I would want the phone on a pay as you go basis and am thinking it would be cheaper to buy a 3G phone than a phone and dongle.
Depending on the phone, yes it can do excatly the same thing, if you have a 3g phone you connect it to your lappy either by Cable or bluetooth and your lappy gets a 3g connection (sony phones work for sure)
as for price plan, look for a phone that comes with an unlimited data tariff/plan the operator won't know if it's a phone or a computer downloading the data (though you may fall foul of any AUP the operator has in place if you download several GB of data)