What's a dozen of night crawlers sell for? $2.50 / $3.00 a dozen. I've been out 3 times this spring (after or during the rain) so far and "picked up" close to 700 or so. It's best to pick just before and after daybreak. The reason I said "picked up" instead of "pulled up" is that there laying right out on the pavement and dirt parking lots that are surrounded by grassy areas. If you use many crawlers during the year a little time this spring pays off during the summer.
So far I've spent about 5 hours "picking" crawlers. At $2.50 a dozen that works out to about $28.00 an hour. This mornings "pickings" went on my garden so I should see the benefits of that for years to come.
Note: See other thread on nightcrawler? for more info.