There is no such thing as "keeping calibration cost on the low side" and still getting high-quality results. There is no shortcut to high-quality video calibration, especially for projection setups. You want to calibrate using a meter that will take readings off of your projection screen. Many of the lower-cost meters are designed for light-emitting flat-panel displays and they have to be turned towards the projector to read the light-beam of the projector. You cannot make readings from the screen with meters like that. So if you purchase a meter to calibrate your setup, you need to make sure that the meter works correctly with projection lamps (some less expensive meters can be OK with plasma but not with projection lamps or with LED or CCFL light used in LCD displays). So the 2 things you really need are: accuracy when measuring light from projection lamps AND the meter can be placed on a tripod 3 to 10 feet away from the screen so that it can take readings from the surface of the screen. The other issue you will have with lower-cost meters is that the filters used in the meter will change as they get older making the meter less accurate as it ages. There is no way to know how long it takes for the aging to be noticeable visually, but most sources say 3-5 years. That means you have to maintain the meter regularly to keep it accurate. BUT... many less-expensive meters have no calibration service so you cannot return the meter to the factory to be re-calibrated (probably with new filters). In that case, the best thing you could do would be to find a service provider like Spectracal who can use an expensive reference meter to create a custom correction table to use with your meter. However... that only works if you use software compatible with the provided correction table. Spectracal's software is called CalMAN and their characterization file will work with their software and may or may not work with other software options. It is for reasons like these that people often opt for professional calibration... the professional calibrator maintains the meter (typically a much better meter than most DIYers would use) and software, etc.
When it comes to keeping calibration costs low, there's a point where spending too little can actually cost you MORE over the long haul (because of having to replace a non-calibrateable meter every 3 to 5 years, for example, or because of the cost of having a new characterization file created every year or two to compensate for the aging of the meter). There's also the issue of software cost... technology changes over time and there are new video formats or features that require additions or changes to calibration software. Seems like every 1-2 years or so, most calibration software is updated so much that there's a charge to move-on to the next version that supports new features. So when it comes to video calibration... it's not like buying a set of wrenches for working on cars... you buy 1 set of wrenches and if you're an occasional home mechanic they can last a lifetime. Home video calibration is constantly evolving and changing. And what you buy today shifts over time and eventually gets obsolete. And if you ever change your projector, you may find that none of what you invested in originally is suitable for your next projector. You should understand all the issues before deciding whether to DIY or hire a professional calibrator.