The Sculpfun S9 is another affordable and worthy of consideration if you are looking for a large work area. Its base version starts out with 410 x 420 mm, but there is an optional expansion set to really go ham on truly large DIY projects; up to 950 x 410 mm. The diode laser reaches an output power of 5.5 W with an engraving accuracy of 0.01 mm, making it suitable for cutting and engraving a wide range of materials, including up to 10 mm acrylic and wood up to a thickness of 15mm.
The simple and solid metal frame can easily be assembled within half an hour and is open to further modding down the road. The laser has to be adjusted manually with screws depending on the distance to the workpiece and the machine doesn't have end-stops, but one of the hidden gems of the is the scale lines on the X and Y-axis. This allows you to get your model's measurements right as well as align the object properly. Plus, Sculpfun ships a steel pad with the engraver to protect your table from laser damage.
The is compatible with various programs, including the open-source LaserGRBL as well as LightBurn, supports the common file formats, and is compatible with both Windows and Apple systems.
The laser engraving machine can typically be found for around $400. Supersizing with the expansion pack adds another $80 to that. You're unlikely to find a larger engraver in that price range.