Anyone know how I can obtain these for an independent shop and what it will cost?
You should contact CAT dealer in your area. I don't know how in US, but we are in West Africa and we purchased ET for about $800 USD. COM-adapter 3 here was about $1100 USD. Regarding Cummins - don't know the price for Insite (but I know you can buy it from dealer as well). The data link adapter was about #1100 USD here. Regarding adapters for both - you can try aftermarket - those are cheap, but I personally never used any (just heard) - so cannot tell which brand is better. Regards, Dima