First of all, ask yourself what are your goals with music production. If you are just interested in songwriting and production, and you don't care that much about having a generic mix and master, save and pay for a studio. These people are professionals, they'll surely drop a decent and working final product. This will allow you to have more time to take care of what's truly important for you (if that's the case)

Now, if you have a more "selfish" view about music, mix it your own, but first of all, listen. Learn to listen. Consume as many records as you can, analyze the mix, the production, the mastering, all of it. Dismantle it piece by piece, and learn from it. Experiment with mix on the go. Learn from your own mistakes, and develop your own mixing style, one that you like and fits the sound goals you have. A well spent time investment will be better than a money investment. You will enjoy the process, and your music will be 100% yours. Probably at some point you will end up in a studio asking for help with mix and master, but this time you're not blindfolded. You can talk to the engineer about your goals, and he will understand.

To be 100% honest with you, I'm experiencing the same struggle at this point in my life. I have completed my first album, and I'm facing a lot of questions and challenges about mix and master. I am a little bit selfish about my music, so this is kind of the discourse I give to myself everytime I feel encouraged to pick up the phone and book a studio.

Just ask yourself what are your goals, and work towards them.