You will want trolling bags, they are built heavier than drift bags. Most smaller boats, especially with running little boards tend to do better picking fish going with the waves, in line boards run smoother this way. Keep an eye on cl or ebay, might find some used boards or bags to help stretch that 300 budget, unfortunately 300 doesn't go far when buying fishing tackle.

Might try contacting some of the captains you know, they might have some older equipment they have cycled out or upgraded that still works fine they might be willing to let go.

Don't overlook running a few dispeys too, they are like 15 bucks or so each and you can run several per side. Won't have the spread of inline or big boards but they do put fish on the boat. I know almost every trip we run at least 2 if not 4. They are not normally our main producer of fish, but seems like during the summer months the larger fish of the day seem to come on them.