How many stamps do I need?

If they the domestic ones weight less than an ounce, $ 0.45 will be enough.

for the international postage it would be best to take it the post office and have them weight and stamp it, It might cost $ 1.05 or more.

Just checked with my stamps.com software we use at work.

First-class mail international letter to Germany which weighs one ounce or less: $1.05
If it’s over one ounce to two ounces, $1.92

If I’m not mistaken, all rates within the U.S. are uniform based on weight and delivery type. By law (?), the postal service can’t discriminate based on location.

@bolwerk the OP has a letter / card for Germany too and yes all domestic postage is the same by weight.

@Tropical_Willie: I got that, and didn’t address it because it was answered. But he seemed concerned about whether it was going in state or out or across country domestically, which sounds to me like he was worried postage might vary based on distance.

If the card to Germany is to a service member or a diplomatic employee it will cost the same as anywhere in the USA if you use an APO/FPO address.