My insurance doesn't cover the hospital grade pump, and it is $75/month. That seems to be on the high end of what others have said. I had the option to rent it for 2 weeks at $45. You might try getting one for a month and see if it makes a difference.
Will your LC work one-on-one with you on his latch? Are you trying the nipple shield with a little formula in the tip or with an SNS? That's what I did when my baby wouldn't latch. And you got him to suckle! That's great!