I agree with Vince. I've had some cheap jerseys as well, and they've lasted pretty good. I can easily get at least 3 years before any issues with the jersey (stitching coming lose or a friend of mine's zipper hook snapping). So, considering you pay $30 for for at least 3 years isn't that bad. I can easily afford to keep multiple jerseys, and wash them only once a week.
I commute to work when weather permits (±30 km each way, 2-4 times a week). If I was buying all $100+ jerseys, I would have to wash them more frequently, and the wear and tear will also start to show.
I have some expensive ones ($100-$200 range) as well, bought on sales from various websites, and the wear and tear starts to show no different from the 'cheap ones'. In fact some of the long tights bought from Nashbar and Ribble are wearing out worse than the ones bought from Ali/eBay.