IMO, a high quality, professionally built pan is cheap insurance on an engine. $500 seems expensive until you frag a $5000-8000 engine.

Now, can you build your own to save some bucks, absolutely. Oil starvation is the big issue with lateral loading, so installing shelves, gates, and extenders in a stock pan to keep oil around the pick up goes a loooong way over doing nothing. Oval track suppliers can provide kits to add capacity. While designed for left hand turns, adding two kits to both sides of the sump is possible. The kicker is that you have to understand the kit size and clearances you are working with to ensure it doesn't interfere.

A more budget friendly version may be the Kevko unit. While not as technically advanced as the Milodon pan, its better than stock.
http://kmjperformance.com/kevko-m302-new-mopar-chrysler-race-x-tra-capacity-oil-pan-360.html