yeah def go to marco rock they are cheapest anywhere, saves you money just takes a little longer to look pretty but personally i would rather spend less and take the time to grow it out, also curing live rock is easy before you put fish in all you just have to wash it off really good and stick in tank with good flow and light if parameters are good then things will prosper and cover the rocks, also those "spots" are coralline algae and they are VERY good to have, some dont like the look and scrape it off personally i think it gives the tank a more natural look, you want this algae in your tank because it keeps other types of nuisance algae from spreading (only certain amount of nutrients in tank, if coralline is using them all then there is non for nuisance algae to grow on) also having alot of coralline in your tank is a very good indicator that your tank is thriving as this is kind of a finicky algae, usually when you get good colonies of this its indicator that your tank is ready to try corals
oh and if your tank is only 29g you would only need like 35lbs rock at most, you still want the fish your going to keep to have room to swim around and yeah live rock is one of the biggest expenses in setting up a tank IMO IF you dont shop around around here i can find rock on sale at petco for like $5plb but there rock is never very pretty and is always really dense, the more porous the rock you can get ahold of the better (more places for BB to grow and is lighter as well)
oh and if your tank is only 29g you would only need like 35lbs rock at most, you still want the fish your going to keep to have room to swim around and yeah live rock is one of the biggest expenses in setting up a tank IMO IF you dont shop around around here i can find rock on sale at petco for like $5plb but there rock is never very pretty and is always really dense, the more porous the rock you can get ahold of the better (more places for BB to grow and is lighter as well)