That's a neat idea you've got! Custom plaques can be a real bread and butter item and laser engraving definitely requires some upfront investment. Getting started means picking up a laser engraver, which can range from a few hundred bucks for basic hobby models to several thousand for high end units, plus design software and a proper ventilation system.
My cousin got into engraving personalized cutting boards and said the biggest hurdle was learning the software and dialing in the right settings for different materials. Once you get that figured out, it's smooth sailing but ventilation is vital since engraving produces smoke, fumes and fine particulate matter that need to be properly managed with an exhaust system or filtration unit to keep the workspace safe and the engravings clean.
What kind of materials are you thinking of working with? Different types need different settings to get the best results.