One word of warning.....it is easy to become disillusioned with amps.
For example, when most people try out amps for the first time. They usually (myself included, when i started out many years ago), don't have enough ped to drop a GOOD number of bombs with them.
People usually try one or two amps, and get a bad hitrate, thinking amps decrease in hitrate. The reality is, you have to spend proportionately more peds to get a good average hit rate.
So, if you are use to 100 ped runs unamped, and have enough to not have the need to completed orders on auction. You will need, as an example, 900 peds spare. So you can turnover easily.
Now take D-class amp. Decay 4 peds.
Instead of 1 ped per drop, it is now 5 ped per drop.
So you will need 500 ped per run, and 900 *5 = 4500 ped in spare. (but there is another added problem, you are no longer selling small amounts, so you will probably need much higher bankroll)
Now most people go out with 300 bombs to reduce outliers. (1000 is more realistic, but most wouldnt do that)
So, now times everything by 3.
You need 1500 ped per run with 13000 ish ped reserve. Just try to get a half decent average return. (not including markup)
So, this is just a warning when trying out amps. MASSIVE pinch of salt when you look at your returns on short runs. TRY AND THINK IN NUMBER OF DROPS, rather than ped spent. This will save you a whole load of heartache.
Rgds
Ace