How do you mange banking and finances?

Paying for Stuff
The easiest way to pay for things in Costa Rica is your credit card, all stores big and small will always take Credit Cards. Credit Cards will usually give you the best FX rate and you avoid having to deal with cash. Important: make sure your credit card does not charge foreign FX transaction fees, there are many cards that don't, but just as many that do.

Getting Colones
Sometimes, you do need cash or you prefer it for other reasons. The best and easiest way to get Colones is to withdraw from the ATM. It will give you the best rate and you don't have to hold on to large amounts of cash. However your bank will likely charge you a fee for using international ATMs.

To avoid those ATM fees, you can open one of many no-fee accounts which will waive all those fees. For example, I use Fidelity Cash which is just a regular cash account in a US bank and I withdraw money from it without paying any fees. There are other options depending on your needs.

There is usually a limit of how much you can withdraw in a given day, however I found that the Banco National ATM in San Mateo allows you to withdraw multiple times in the same day and somehow avoiding that limit. I've tested it by doing two 300k withdrawal transactions back-to-back without any issues, while officially my limit is less then that. Basically experiment!

Using Dollars
You will find that most vendors and even many stores accept dollars directly. Simply ask your vendor or store and see if they accept dollars. Also be sure to check their conversion rate, usually they will use the standard conversion rate as shown here.

Large Purchases
If you need to make a large purchase such as a car, you will likely want to do an international wire. There will be a fee most likely that your bank charges depending on the type of account you have, there will also be a fee that the recipient bank will charge that you will not see, but your recipient will. There is no way to avoid the recipient fee, but you can find US banks that don't charge wire fees depending on the minimum balance you have in your account. For example the Chase Saphire Checking account will have no fees on wires and will also have no ATM or FX fees.

Where to keep your money
Its best to keep your money in your home country if possible, the digital services and level of security as well as things like FDIC insurance are much superior to what you find in Costa Rica. In fact, be prepared to be quite disappointed with banking experience here, both in person as well as on-line, they are quite antiquated.

Moving Money into a Costa Rican Bank
There are two approaches here depending on the amount. For small amounts (under $500), its easier to just withdraw that amount from an ATM, using the no-fee ATM card described above and deposit it back into the bank directly.

For larger amounts, doing a wire transfer is best. In general its recommended to do wires under $10,000. Wires above $10,000 have a chance of being flagged by Costa Rican anti-money laundering processes and then you will have to go into the bank and provide documentation as to where you got that money, which can be painful.