The best way to get a quality LPM for relatively cheap is to buy an Ophir sensor off of eBay, and use it along with a DMM and two 9V batteries to make an LPM. Here is what you want to buy:
Ophir Laser Measurement 20c A 1 Y Sensor Laser Power Meter LPM 1706111 New | eBay
This sensor outputs 1mV per mW of measured laser power. Therefore you just have to use a cheap DMM to measure the voltage signal from the sensor, and that's your LPM. There are many threads about this method, just search the forum for 'ophir'.
The ophir sensors have a very fast response time (<1s), are very accurate, and many forum members have them. (They can also be used with other LPM systems, if you ever decide you want a dedicated LPM that does data logging, etc, in the future.)
There are ways to get slightly cheaper LPMs (e.g., $100-$200), but IMO these are not really worth the savings, as they use a different kind of sensor (TEC), which has a slower response time, which means you have to wait upwards of 30 seconds before you get an accurate reading. It's worth spending a few more bucks to get an Ophir, IMO.
