Newbie here also.
Using the start collecting box, you can get a few MLs from strike/breacher team shas'ui, and a few marker drones. At that stage (~500pts) probably only have enough MLs to accurately hit 3 times, which for that army would only really benefit from the first ml.
One of my next purchases was a pathfinder team. as stated above, very useful being able to let off dedicated ml without worrying too much about being down almost 10% of your guns due to opting your shas'ui to fire a ml.
one tip i have come across and use is to role ml one at a time, especially when trying to get the first ml on a unit. subsequent ml can benefit from the first hit, but not retrospectively (i.e. misses that came before the hit) if aiming for the 5 ml bonus, roll individually until you get the first, and then roll the rest in groups until you have what you want.