As far as a DMM goes..
It seems the low end Aneng 8008 stands out in terms of value and can be had for around $15 or so. I would get that one.
I have a Unit-T UR61E DMM which gets a lot of use. It stand out on value in its price range if you only do low voltage stuff (like me). It was around $50 on ebay.
Also, a few months ago I bought a $2 voltage regulator "breadboard power supply" from China (manufactured by yuwibot (?) or something like that) that clips to a breadboard and supplies 3.3 volts (or 5 volts) if you plug an external wall wart that supplies 7-12volts to it. .
Its convenient and it works, however you should remove the USB connector from it or put tape over it.
It has several issues which you can Google about/for.
Still, its useful for powering standalone breadboard 3.3 volt projects..
For my soldering iron I am currently using a cheap clone of a Hakko that adds digital temperature control. Its a mixed bag. It was around $40 from mjpa.com here in the US.
Similar irons are much cheaper on ebay. I have a bunch of tips for it and they make it much better than it would be otherwise but it still has an issue in that the thermal contact between the heating element and tips could be better and there really is little I can do at this pint to improve that.
That means the temperatures it reads are inaccurate. I didn't realize this for a while as a beginner.
So now I am hoping to find a Hakko FX888D on sale somewhere.
Other very useful, very cheap tools.. I have an "AVR Transistor Tester" from ebay.. (see this article - as well as a huge thread here- for more about it:
https://www.mikrocontroller.net/articles/AVR_Transistortester#Introduction_.28English.29 ) Its extremely useful for things like ESR testing of old capacitors. I paid around $15 on ebay but now they can be found for as little as $7.
They also test inductance - capacitance - most semiconductors and identify the relevant parameters of around 90% of unknown or private labeled two and three terminal parts.
The ESR testing capability is essential for repair of old electronics.
I also have an old Tek scope, one of the first models with any DSO capability but it is basically analog... Its a classic, kind of but it takes up a lot of desk space.. so right now its usually used sitting on the floor with is screen facing up. A non-optimal setup.
I also have a cheap, generic (Sigrok.org) -Pulseview-compatible 8 channel logic analyzer - You can find them now for $10 or less.. Its really useful.
An adjustable constant voltage/constant current supply is kind of essential when you are doing low voltage stuff, because the adjustable constant current can prevent a wrong connection from damaging precious parts. The module in the recent video has adjustable current limiting and would do this adequately.
(before you connect power to your circuit, limit the current in the circuit to what it is supposed to be plus maybe 15-20% even if something inside your device shorts the power supply rails. This won't have any effect unless that current level is reached. Then, it will limit the current at that value.)
I have a bunch of breadboards of varying quality.
The smallest ones get used the most. If you can afford to buy good quality breadboards its worth it.
Its good to have a bunch of test leads of various kinds. Also, solid hookup wire (for breadboards, especially) and some "dupont cables" short color coded jumper wires with female or male headers make it easier to use them as intended. Use the color coding to identify different kinds of connections. It makes it much easier to keep track of what's going on in a circuit.
For a soldering iron I would make sure the tip is grounded and the tips interchangeable. I would start out with a hakko clone but make sure you get a good value and pay the least for that clone.
I recently got an assortment of tips which contained most of the popular shapes for less than $5. It was a knock off but so far the tips have held up well.
That makes all soldering much easier, having the proper tip for what you are doing.
If you can spend a bit more to get a Hakko Fx-888d - by all accounts do it, it appears to be worth the money. (around $100) if you do a lot of soldering.
The temperature it shows is more accurate, its thermal transfer is tighter, and much better regulated. Making it more of a pleasurable experience for the user. Otherwise once you realize your soldering oron has this thermal lag you're going to need to keep adjusting its temperature to make up for that shortcoming and you'll realize that its potentially bad for components to be exposed to higher temps than they should be as you attempt to make up for the thermal lag.
Its good to also have other means of heating boards while you are soldering them available.