Don't focus too much on the cost of the lab equipment. It'll seem like a lot if you add up the costs of everything you think you might need all at once, but that's not the right way to equip a lab.
The key thing is to buy what you need, when you need it. Always be ready to buy a new tool, but don't actually do so until you have a compelling reason to spend the money.
I started out with a simple 'hobby' lab, consisting of:
- a good, solid bench with ESD mat
- a 4 channel analogue 100 MHz scope
- a reasonable soldering station
- a very cheap '830' multimeter
- a good selection of hand tools
- a laptop PC running free schematic and PCB software
That's about it. It was enough to tinker and play with at home, but really wasn't up to the job of working professionally.
No PSU, no function generator, no spectrum analyser, no logic analyser.
First was an update to the IT equipment. Out went the free software, and in came a copy of OrCAD PCB Designer, which has been an indispensible staple of my business ever since. Also a NAS unit with a UPS, and a robust backup solution. You'll need somewhere to store customer jobs, and you can't afford to ever lose data to a drive failure.
Next, the scope had to go, replaced by a Tek TDS754D. I needed the 500 MHz bandwidth, for a specific series of customer jobs.
I bought a used, and quite old, Fluke multimeter too, for confidence and the sake of appearance in front of customers as much as anything else. It confirmed that my '830' was in fact perfectly accurate and usable.
It's very, very rare indeed that anyone actually questions the accuracy of a measurement I've taken. There's no rule that says you "must" have a calibrated meter just because you're a "professional".
That said, several years later, all my equipment has been upgraded apart from the bench.
I sold the Tek scope and now have two MSO-X3000A scopes instead; one 1GHz model because I needed the extra bandwidth for a specific job, and one 500 MHz model which I take to customer sites.
I have a few multimeters now, of course. Most often I use a 34465A, mainly because it has a permanent place on my desk so it's convenient. I like the data logging features - but more often than not, I could use a much more 'ordinary' handheld meter
I also have a Fluke 289 which I bought for a job that required logging a vehicle's battery voltage while it was in motion It's now a 'travel' meter which I always tend to have with me when I visit customers, on the basis that although it's not actually that nice a meter to use (rather slow, poor display contrast), it can do pretty much anything.
The same goes for the signal generator and impedance analyser. I don't use them much, but for the jobs that require them - and justified their purchase - they're invaluable.
For a time I did keep a few saved searches on Ebay, and picked up good quality, general purpose equipment (power supplies, microscope) when it came up for sale at a good price - but although I use my power supplies and microscope regularly, the fact that they weren't bought for a specific job makes them unusual.