Wow! Lots of questions- but all of them good!
First, you will have no problem with staying in your price range (you'll live like a king) and have the commute you desire. I know of several properties that will fit the bill on that. Your credit is good and you have lots of financing choices depending on what you are trying to achieve (low downpayment, a low payment,s low interest rate, etc.).
When you purchase a home as a buyer generally the seller pays all commissions. This is not a buyer's expense. If a house is listed, then the seller has already agreed to pay the listing agent "x" amount. The listing agent them agrees to pay a buyer's agent from their proceeds. If you decide not to use a buyer's agent and go directly to the listing agent depending on the private listing agreement between the seller and listing agent - the listing agent will make the full commission. Not you, nor will you have to pay the commission.
The only time you will have to pay the commssion as a buyer is if you signed an agreement with the buyer's agent stating if the seller refuses to pay (like in a for sale by owner situation) that you will pay it. Know what you sign.
A good buyer's agent is worth every penny and then some. 99% of the time you pay nothing and they protect and negotiate you more. Would go to court unrepresented? He who represents himself usually has a fool for a client (I believe O W Holmes said that). I have seen nightmares that cost folks their lifesavings just trying to save a dime. In the end they didn't understand how they let it happen to them.
Be careful of foreclosures with certain types of loans. If repairs are required and most foreclosures are sold "as is", the deal may not work or you might get stuck paying prior to closing or worst - financing repairs into Your loan. There are good deals all around, not only with REO (real estate owned property), so don't limit yourself.
As far as three years down the road with your agent - most are generous with past clients. This is as individual as can be. Some companies do not allow their agents to make special deal - they mandate how much can be charge. Others have more controll of their business paractices. Three years - a lot can happen and you may meet in your new town a Realtor who becomes your friend through church or work, etc. - who knows your spouse might want to become one. Let's not get the cart in front of the horse.
You are in the drivers seat - it's a buyer's market and you have so many things that are going your way.
Welsome to the area and best of luck. Let me know if I can help.