Mill Creek Entertainment released a Complete Series collection in 2010, which should still be in print although it is not listed as available on millcreekent.com. Some SuperTarget stores had this title, along with a few other of MCE's animated DVDs as a store promo for a mere $5... but that was at least 2 years ago. You should be able to find both new and used copies on amazon for between $10-25. And used copies of BCI's 2 Volumes are currently selling for less than $5 each on amazon.
MCE also released a 16-episode collection which you might still be able to find in stores. I saw a dollar store in a local mall just this week that was selling the 16-ep collection for only $1.50.