If you're just starting out as a raw feeder, the process of it all can be a bit overwhelming. Frankenprey guidelines are general in their inclusions and small whole raw prey is difficult to come by. Some of us have local butcher shops, markets, grocery stores, natural specialty stores, etc. and may purchase organs, bones, and meat from various vendors. For others, this may not be plausible, so purchasing raw is best done with online merchants. There is no good reason to not feed raw.
We feed a diet of Frankenprey and whole raw prey. Our Frankenprey parts are purchased through several sellers. Whole Foods frequently has organic chicken livers for sale; at times, chicken hearts. We buy preservative-free, hormone-free, and antibiotic-free calf hearts, calf livers, calf kidneys, and lamb kidneys from our local butcher shop. Grocery stores will likely have turkey and chicken livers and hearts for sale, as well as gizzards, both in frozen and fresh forms. Some will have raw beef kidneys. Raw meat is the easiest to come by---make sure to buy from natural/organic sources. Anything else comes from diseased, injured, and confined animals.
When starting out as a raw feeder, you cannot and should not feed thick, hard, or large bones. Small carnivores can break and fracture teeth and choke on bone pieces. I cannot stress this enough---it happens and we have seen it happen. Animals that have been fed a canned/dry diet and are being transitioned to raw have untrained, weaker jaws that have lost biting, chewing, and grinding power. They must be retrained and their jaws strengthened over time---so transitioning from chewy raw meat to neck bone strips to whole poultry necks to chicken wings/Cornish game hen/whole raw prey is essential. Skip this step and you risk potential injury or death---choking, intestinal issues, tongue lacerations, broken teeth, digestive obstruction, etc. We purchase frozen chicken necks from Whole Foods. These are thawed, skinned, and then cut into six long strips (meat included, but fat removed). Only many months later should you move up to harder bones (whole raw wings, Cornish game hen bodies, whole quail/chicks/adult mice and rats, etc.). Dense and thick meats also strengthen jaw muscles and bones---these include beef, tripe, poultry gizzards.
I visited a large, but local ethnic store once and never went again. While the variety of organs is there, product knowledge is lacking. This doesn't happen at butcher shops or the meat department at Whole Foods. It took a couple of raw meat department associates to provide me with their distributors' names and they had no idea what terms as "organic", "free of hormones and antibiotics", "free-range and ethical", and "preservative-free" meant. They thought I was from the Health Department---asking the questions I was asking. Red flag raised and that was my first and last trip. The variety offered didn't compensate for their shady distributors and the low quality raw meat. I'm not feeding my guys that trash and I am not supporting raw like that.
Another option is to search the Internet for local raw pet stores that specialize in natural and raw food for cats and dogs. These will likely sell natural dry kibble mixes and canned food without chemicals and preservatives, and hopefully have a few freezers full of prepared raw food. Prepared raw mixes may be used in transitioning a carnivore to a fully raw diet, but don't get stuck with them---transitional only.
Online vendors, when domestic, trusted, and follow regulations to a tee, are awesome.
We've ordered from RodentPro that specializes in whole raw prey. We have also become loyal and repeated customers of Hare Today and My Pet Carnivore. The latter two offer so much that I would never find elsewhere---unbleached tripe, pancreases, lungs, organs of all sorts, whole animal carcasses, ground chicken feet and gullets, etc.
There are plenty of raw sources to buy from. Raw meat is the easiest to purchase. Butcher shops, grocery stores, and online vendors will have various organ meats. Bones are also available, but the bone size and thickness set the buying guidelines. I would never, ever recommend purchasing raw from overseas or through untrusted, shady companies. Do your homework.