i'm not really sure just how low of stakes you are talking about...but at 25nl i pretty much always raise a min bet w/tptk...this gives you alot more information and at least on 25nl you have a better hand than the min raiser 80 percent of the time. this goes for the turn too, there are alot of times i will cbet on the flop and some donk will min bet into me...and most of the time i raise and he folds or makes a hesitant call and it is check check on the river w/ me winning........min raises on the river are at the very least a call most of the time i'd say...for me it is all the time at 25nl...because it is usually some guy looking for a cheap showdown w/ his tpbk or some random middle pp. i'd say folding on the river is pretty much also a sucky idea because if you have been betting tptk there will be a pot and you only need to have a winning hand against a min bet ever so often (avg pot/min bet) to make it +ev on the river.