Money, money, money, always sunny...........
I can only throw in my $0.02 on money.
1) Ensure that you have two ATM cards. This way if your US bank blocks one card - fraud protection - until you spend a year in interactive voice response hell to unblock it, the other can be used. Many "regulars" use a PayPal card for primary or secondary.
2) On arrival if you do not have any Soles and are going to use a "green" taxi go to the ATM in the luggage hall and withdraw S/.300 from that machine. Do not use the desk money changers. Even Jesus kicked their ass out.
3) If you are bringing in US currency make sure it is almost new with NO tears, ink stains etc. and I recommend only $20 notes. If you are not brining in cash, also withdraw $200 from the machine in the luggage hall. (Yes, the machines are bi-lingual.) That amount is the max. on that specific machine.
4) If you need more dollars once in Peru and the amount is above $200 try and use Banco Continental machines as they typically allow up to a $500 withdrawal. Many Global and BCP machines are now a maximum of $300 or $200 to maximise transaction fees. And you can have two machines next too each other with different max withdrawal amounts! Most machines also only allow S/.500 withdrawal at a time so you are actually better off changing the ATM US$ in the street. Just make sure you know the Spanish for numbers 1 through 9 to double check the rate. (Never trust the street vendors calculators! Work out what you should be getting BEFORE changing. The rate doesn't change that quickly or much.)
Polvo