I use a £250 bosch one, comes with 2 batts, is well worth the money, depending on what you're doing with it, serious amount of kick, but so fkin heavy, man it really is, 19.2 volt.
Just watch the battery type, don't touch one with NI-CD, LI-PO is the best by a very long way, but NI-MH is more common, excellent performance battery wise, but they do tend to discharge quickly when not used/charged, ie if left for a week or so will have lost a bit, but they don't suffer memory effect like the NI-CD ones do, though it should be impossible to get NI-CD as mostly banned now.
I love makita myself, nice light and powerful.
tabetha