Hi 

I’m building a block garden room for my son. 
Never done anything like this before but I have thoroughly researched. 
Footings completed and 3 courses of engineering bricks completed, 1 below ground level. Hardcore , sharp sand , DPM , rigid board and 100mm concrete to be completed next week..

will then roll out dpc and start blocking.

the room measures 5m x 3m and I want to get blocks perfectly level. Would prefer to use a line laser for accuracy and I would buy one. Don’t want to pay for a rotary laser that I wouldn’t probably use again. Would a line laser provide the horizontal line I could lay blocks to , just like a string line. What are the alternatives on getting courses perfectly level. Thanks for your help

Dewalt do a green line laser Cheap as chips 

The go-to on most sites is the basic dewalt one:

 

Don’t buy the cheap Chinese dewalt copies (with LG at the end of the model number). 

Spirit levels work,  and remain useful thereafter.

If you go that direction, ask more more advice.