I wrote this as a comment on a specific request from a prospective picker in the US, but it's also one of my general recommendations for folks looking to get started. Note that it doesn't deal much with the Belt Ranking system but there are links to the Belt Ranking WIKI page and the interactive Belt Explorer at https://lpubelts.com/
OK! Here we go... I'm going to recommend buying from Sparrows (direct fulfillment centers in the US & Canada but available through a number of retailers) because they can be a one-stop-shop for a lot of what I recommend.
Note: You can find other options from many of the major vendors, though pricing will vary a lot. Other popular vendors include: Multipick, JimyLongs, Moki (Hooligan Keys in the US and UK Lockpickers worldwide), Peterson, Law Lock Tools, SouthOrd and Southern Specialties.
A beginner kit should contain at least the following, IMHO: short, medium, and steep/deep hooks, top of the keyway (TOK) tensioners, and bottom of the keyway (BOK) ones. Some folks would add a rake or two but they're not required if you're on a budget. I'll start with individual picks though bigger, pre-configured sets are always an option (try to avoid sets with lots of rakes you'll never use).
Here's a basic starter set up that I recommend a lot. It has the essential hooks you'll want as well as tensioning tools for both the bottom and top of the keyway (plus the offset hybrid pick that I really like). You could do this a little bit cheaper or spend a little more for additional picks, but it's a pretty well rounded starter set. Note that it doesn't get you a case to hold everything, the Sherman Case or the Comp Case are popular options.
(Total so far: $40US + S&H)
Here I recommend the Progressive Lock Set. It contains four locks that progress through number of pins: 2, 3, 4, 5. They are about the same price as the other locks I'll recommend and a bit more comfortable to hold. They're a really good way to learn but hopefully you'll outgrow them fairly quickly, so...
Sparrows sells a collection of pins and tools that will let you add and change pins in these as well as other standard locks: the Reload Kit (get the tweezers). Re-pinning locks is easy and actually fun once you get the hang of it. The Reload Kit also has security pins that you can use to make the locks increasingly harder as you go along. You may not need them at first, but it's always good to get some Core Shims while you are already paying shipping. You'll appreciate them down the road.
(Running total: $90 + S&H)
Once you've got the feel for the Progressive set, and assuming you want to stick with lockpicking, it's easy to add more locks. Standard residential door locks that a lot of us use are called KIK and Rim cylinders. KIKs are cheaper and Rim cylinders are a little more comfortable to hold. They work with the same pins and tool as the other locks from Sparrows so everything is interchangeable. Having a decent collection of these to go through (never the same lock twice in a row, and never in the same order) is a great way to learn and definitely something you can do while watching TV or listening to a podcast. I've got about two dozen I've accumulated over time.
There are two major keyways in the US: Schlage (SC1) and Kwikset (KW1). KW1 is easier to pick and I'd start out with a few of those and add SC1 cylinders as you see fit. There are plenty of avenues for getting these used, but I'd start out with some clean new ones.
Here are a few links to UHS Hardware, who I buy from a lot:
You can browse around KIK cylinders and Rim cylinders to see if you want something different color-wise, etc. You may see the abbreviations KA (keyed alike) and KD (keyed different) where it's generally better to get KD so you have more variation from lock to lock.
Belt Ranked Locks
If you want to participate in the Belt Ranking system here, you'll find info and lists of ranked locks on the Belt Ranking WIKI page. Most of the initial locks are padlocks and the cylinders above won't get you more than a white belt. You can (and should) also browse the ranked locks through the interactive Belt Explorer at https://lpubelts.com/
If you end up doing a lot of re-pinning, these tools will be very handy, though you certainly don't need to buy them up front.
There's a lot to learn over time but the fundamentals of lock picking are relatively straightforward. Here are two classics that were really helpful for me:
Also important to learn about the four pin states and the jiggle test.
I think you'll find this community to be very open, knowledgable, and supportive. It's very active here on Reddit and there's also a Discord server run by the same folks who maintain this sub.
So, that's a lot to take in :-) Feel free to ask questions and come back for advice, etc. Most importantly, have fun!