Lower mu ones and a lot of uses. If beginning the game less than level Ground Assesment or so I wouldn't use something above a level 4 finder amplifier (L). Planetside is about being able to throw several drops (100+) before amp breaks. Also look for zones that pay the MU of amp with the materials contained within + tax. Level 1,2,3,4...would be my suggestion and if you have less than 500 ped on pedcard balance don't go higher than a level 1 or so. So you can rotate a lot of materials.
Terra amp 1 and Terra amp 1 'Athena' are good choices. Just watch the minimum required skill level and make sure you have enough peds on your ped card to handle longer down swings.
