Bernina Dealers are not allowed to post prices or sell online. One way Bernina has of protecting dealers territories. That said, some will take an order over the phone and ship accessories. And as KLO said, there are always Bernina feet on ebay but you need to make sure is is genuine Bernina. You want to make sure the white sticker with the number looks right, but the picture may not be the one you get so check feedback before you buy if you go the ebay route. I bought one once that turned out ot be a poor fake - the needle hit the foot when it lowered. Fortunately, the seller took it back.
I have had a 440 for over 6 years and I absolutely love it. I has had regular maintenance but never had a problem otherwise. The embroidery unit had a bad board when it was new but has worked great since it was replaced. I also brought a vintage Bernina 910 (little sister to the 930 without decorative stitches) for a backup machine and it is still going strong too. My only experience with the new 830 was an embroidery project class with a Bernina educator where they furnished the 830s for everyone to use. It was a great machine, and I loved the jumbo hoop. The jumbo hoop is the only thing that really tempts me, being able to quilt a 12" quilt block at once instead of re-hooping. I can only do 6" designs.