I would call and ask for information, not call to complain. The first may get action...the second will, at best, result in eye-rolling.
That said, the whole field trip thing differs from district-to-district.
When I taught in the inner city we were required to take our kids on a minimum of one enrichment-based trip a month. You read that right!
When I taught in the burbs in MO, the PTO's gave each grade level a set amount of money and you could do with it as you wished. However, due to a lawsuit ("a free public education") we were never allowed to do fundraisers or ask for money to cover the costs.
The district where I'm at now has really curtailed trips this year. Why? In the old days you could have the bus drivers drop you off and pick you up later. Now, with a new contract and policy in place, the bus driver has to stay with you all day and has to be paid for the time from half an hour before departure through half an hour after return. Add to that the bus price and a surcharge for fuel and what you get is teachers saying that they aren't promising any trips at all this year.
And, that's fine with me!!! Last year my first grader's trip to the zoo cost me $25. I can take him myself for $5!
As a teacher, here's my best advice: if you are upset with something that has gone on at school, rant and rave to your spouse, your best friend, your sibling, etc. Get it out of your system. Then, calmly call the school...preferably the person who is your direct contact (meaning...don't call the counselor just because you're uncomfortable with the teacher, etc.) and ask for information. Then, share your concerns. You don't want to get a reputation for being "that parent".