I have 3 US Airways vouchers ($75, $100 & $150). I was told that I can only use 2 max. Does it sound right? Is there any way to use all 3 vouchers to purchase a ticket?

Not necessarily true. It depends who you ask. I once redeemed more than two vouchers through a travel agent I used often.

Another time, I was told by a NW agent that I could only redeem one voucher per ticket. I then explained that I got the vouchers because I complained about poor customer service and I'd complain again if I had to.

She accepted the vouchers.