Lump is better than briqs because lump doesn't have fillers and binders. The lump is all wood. My preference is Royal Oak. I've been using it for a number of years. It's quick lighting, good burning and no offensive orders.
As far as wood is concerned, it is available at Ace Hardware, Academy sports and other big box and hardware stores. There are also a lot of wood sellers on Craig's list. Other sources are orchards, tree trimmers and landscape contractors. Try to find fire wood. You will like it better in the long run.
I get this at Home Depot. Not cheap but like you I'm just getting started with an offset myself and am looking for a wood supply. I just did a butt yesterday using brickettes and lump to start the fire and wood from then out. You're not going to keep a "steady" temp like an electric smoker. I was able to keep it between 215 and 265 and it came out great. 7# butt and the bone fell out at around 10 hrs. 😊