I had the same question a couple of months ago when my vacuum cleaner broke. Fortunately Consumer Reports had recently had an article on vacuum cleaners, so after reading the article I bought a Bissell Powerforce bagless at Wal-Mart for about $50 and I'm very pleased with it. It picks up pet hair and dirt much better than the old one, which cost twice as much.
Well I dont know if it is inexpensive but it is very important the vacuum has a power head to separate the carpet fibres to lift the pet hair, I have a SEBO and with several cats it does the job perfectly. I found cheap vacs with no power head are useless.
