Pets
On the plus side, pets generally do not need the same variety of different foods as humans.
On the minus side, explaining to your pets that their diet will be changing because you cannot get their usual food is not going to work well.
Pet food tends to come pre-packaged and has a reasonably long shelf-life so — finances and space permitting — you should not experience any issues building up a stock of food. Don’t forget the other necessities for your pets, though; litter, flea and worming treatment, bedding for those animals which require it, water treatments for fish, and so forth. And if your pet has to take prescribed medication you may want to talk to your vet about getting additional supplies.
Wildlife
If you currently feed birds or other wildlife, and you think that you will need to cut this down due to lack of money or lack of food availability, try to make sure that you taper the food availability gradually. The wildlife may well have come to depend on your food as a regular part of their diet and, especially at the time of year when they may be starting to breed, they will need time to adapt.
If you can’t cope
Please don’t just abandon your pets! There are many local rescues who will help if you really can’t afford to keep them. You can usually find them via social media or by asking around in your local area. (And if you can afford to donate some money or food to your local rescues, it would doubtless be very much appreciated.)