Catering business needs large and adequate pots and pans. This is your first major and necessary tools. IF you buy an ongoing business these will be part of your purchase. If new you would have to buy these expensive tools and this will form a major part of your catering business.
The investment in the food industry on equipment keeps its value well. There is a good resale value and market for this anytime.
This is an investment you can hope to get back when you do not want to continue your trade anymore.
What is first?
Do you want to go used or new?
The question you need to ask if you are starting new is whether to buy used or new pots. New and used both have their plus and minus. You can always find used in auctions or stores in a big city.
Go to these auctions and buy a few necessary containers. Even if you do not buy you can gain value experience is pricing them.
When you go these places you will also find out the availability of smaller vessels and pans. The smaller ones are the most used items in catering.
The auction batch sales will have these smaller items which are less expensive than the larger ones. A batch may contain many items and some you may need and some you do. Be careful buying in bulk as you may have to buy more than what you need just to get one or some items.
Pay attention to used stores related to restaurants.
These are invaluable locations for your purchase of used items. There is bidding war here and pries should stay well within moderate ranges. Here the biggest attraction is you just buy one that you need at a time. There is no bulk purchase or utensils.
There is a good possibility for smaller events you current kitchen utensils will work. Many caterers do work out of their homo and use home items to begin with.
Do not be discouraged by this suggestion and that should not limit the size of your bookings. You should be looking for rental kitchens of commercial nature close by. These are excellent in providing you with necessary large vessels, pots and pans. They also provide many smaller items for every day use. The prices should be affordable and reasonable. Try shopping for a few in your area till you find your fit. Many start and stay with these rental kitchens for a long time.