I've still got 11 months or so left on my 2 year  family plan with AT&T, but I'd like to buy an android phone now and  sell my existing Samsung Impression. What is the cheapest Android phone  that will not switch me to the smart phone data plan? I'm currently on  the $15 unlimited dumb phone plan. The G1 looks cheap, but will an  unlocked one trigger the plan change with AT&T? Is there anything  else I should be looking into?
				
			 
	