Bow tuning

What are you trying to do?and has nocking point been set?Read up on paper tuning and how to use a bow square
If you will get on the web, see if you can find a resource on paper testing. Draw length has to be right and arrow stiffness has to be right.

You can learn to tune your own bow - just got to read up on it some. I always like to shoot an arrow at 50 yards after I thought I had it squared away.

These days - I have the bad shoulder and shoot a crossbow. Not much tuning to a crossbow - wax - wax and wax some more. String and rail.

Good luck.

To tell you the truth, There is a lot to it if you really want to get into it. There are countless videos on YouTube to do stuff with, but I don't have a bowpress for the big ticket items. My buddy owns a bowshop, so I know how involved it can get when you start trying to time cams, and compensate for stretching cables/strings. Look at some videos on bare shaft tuning, and build a paper trap... I keep one arrow out of every dozen I build bare shaft literally as my tuning arrow.

If your bow has been set up prior, just keep performing maintenance checks on it. What I do, is a simple tune in my basement many times a year via paper tuning. If things are changing quite a bit, I know it's time to look deeper.

Once a year I go to my buddy n have him look the bow over. This year I'm due for a string, so it's gonna get fun as far as maintaining tuning.

It's not a hard thing to maintain if your setup is solid from the start. The archery talk forums are a great resource if you can sort through the arguments
If $79 is based on an experienced tech's opinion that the job requires three hours of work, I don't think that's exorbitant. The other shop probably thought it was four or more hours of work.

Youtube is your friend if you want to learn how to DIY. But you will have to invest in some equipment and supplies. Money spent either way.
What every body else said X2. Pretty much comes down to fine adjustment of the arrow rest, centered ( left or right) on the string. And up and down (knocking point).
Pit falls:
Cam timing. normally a string problem or limb out of adjustment
Not enough arrow spine. (stiffer heavier arrow or reduce draw weight)

I have found that after the paper tuning,if you shoot at a target butt 70 yards away, with the sun low you can see the arrow flight very clearly due to the sharply upward angle, making picking out porpoising or fish tailing easily. It is very satisfying to tune it yourself. Be patient. Enjoy the journey.
If you're serious about archery, learn how to do it. Online resources are readily available. One of my go to sources is the Easton bow tuning guide. Please note that just because your shop says things are tuned doesn't mean fixed blade broadheads will shoot exactly like field tips. In my experience, further tweaking is almost always necessary. I use both bare shafts and the walk back method to tune. Also keep in mind that bow tuning is static. It shifts with stretching strings and cables so being able to tweak things on your own is essential.
Lots of good info on archerytalk also. There really is a lot to tuning a bow but it's nothing overly complicated, just takes time to figure out all the various pieces to truly tune a bow.
I enjoy anything everything archery so tuning my bow is enjoyable. I've never had a problem tuning. Archerytalk is where I learned a back around 2000. Paper tuning is all you need to worry about unless you decide to shoot tournaments. Then you may want to worry about tuning a little finer. The tools you need are not that much and if you plan on doing any work should get anyhow. For a press you can make one pretty easy but I just bought one of those portable presses. They are basically cables you tighten to pull the limbs in. One day I will get out there and make a real one. There are plenty of videos on YouTube. As far as timing your cams, well you only need to worry about that with dual cam. If you have a solo cam then no timing is involved. I know some people have wanted their cams tuned with a solo cam. I just laugh because that top wheel is round. Give it a shot. It's actually not bad to do.
As others have mentioned, archery talk is a great resource. I think there is still a PDF you can download called "the nuts and bolts of archery". It's a great read and a great reference if you own a compound bow.

I have an elite and have to time my cams. I bought a 'bow time machine' from a member on AT that doubles as a draw board and a press. It allows me to time my cams, check draw weight, replace strings/cables and do everything I need to do to my bow. I can't remember how much it was, but it allows me to do my own work.

It'll pay for itself fairly quickly at $80 to $120 a trip. Especially if you shoot quite a bit and replace your cables/string regularly.
I don't paper tune where I work, but will check/time the bow, check/fix peep alignment, and make sure everything is squared up for $25. I will tell customers how to walk back tune at their house(it lets you shoot the bow while tuning). The only way I charge more is parts, like strings, cable, peeps, etc.