I have both the DC30 and the DC40 collars for my Astro. I used the DC40 for the first time this past week and can't say I'm sold on it being better than the DC30. It tends to drop communication more frequently and it goes through its charge more quickly. It also doesn't like to connect to the 220 as quickly as a DC30. You might think about a DC30 instead. I don't have any leads on where you can get them, other than the usual online sources like Lion Country Supply or Dogs Unlimited.
I called about one yesterday and they told me the dc30 wasn't waterproof. Also you can program the dc40 so it will not transmit as often to save your battery. Like every 2 minutes. Now I am not sure what I want. I did find out that the dc 30 is $100. cheaper.
Thanks for your input
I wouldn't worry too much about the waterproof thing unless your dog swims with it regularly. I've not had a problem with the DC30. I understand there is a software update for the DC40 which may help but I have not tried it.
You can set either collar to transmit less often to save battery. I use mine for grouse hunting primarily and 2 min is a long time. I have mine set to 5 sec and that even seems long sometimes.
Regarding prices, those seem about right. I doubt you will find much better.