School me on surge suppression/power conditioning

Long time lurker off and on, new member. 

I moved to a rural area in north idaho that sees some surges(flickering lights) now and then plus some quick outages that last a few seconds to minutes to hours to days. Our area has all underground power and we have the big green transformer 350 feet away from our house down the driveway. Meter is outside the house on a pole that feeds 3 separate buildings. Our pump house, the stand alone garage, house.

Before i install my old school deftech powered towers and center along with my parasound hca1205 and Yamaha 3080 reciever id like to do some things to prevent damage to this equipment. I dont have a lot of money, and it IS a triple wide MH. So no room left in the inside breaker panel with it full of tandems and quads already. Thinking number #1 is a panel mounted surge suppression at the outside meter/mains shut-off to the 3 buildings. Im comfortable inside a breaker panel unless its pulling the meter. Each building also has its own breaker panel with main lug panel but too are also full since they chose the smallest panels.

Ive been reading, and definitely overwhelmed and confused. Ive got maybe a $500 budget for now. Just had to replace my heatpump ($6k)and have backup heat(woodstove $10k) installed so im kinda tapped for a few months.