When my first nic and flavor order came in, I stopped at Tractor Supply on the way home for a couple syringes and needles.
We can, so I already had plenty of serviceable glassware around.
As I got a couple mixes under my belt, I started getting an idea of what else I'd actually need, and have added a few flasks and beakers (in sizes that made sense after I'd mixed some) to my Amazon cart when ordering.
I've now got something I want to mix in 50mL or larger batches, and have a PC fan and a couple magnetic stir bars on their way - like $10 investment.
I've already got the potentiometers laying around to make the fan variable-speed, and my bench breadboard is rigged for the standard guitar-pedal sized barrel power-adapters, so I figure I'll mount one of those in the fan, and be able to run it on my bench power supply.
I'll have a damned capable magnetic mixing plate, up and running this weekend, for less than $15 in parts.
I'm sure I have less than $60 in DIY hardware, including the tool box I keep it in, and it is plenty good-enough kit.
I just built one of those magnetic stirrers, and here's my experience if you're interested:
Don't bother with the speed control pot - normal ones can't take the wattage and burn out quite fast.
You may have read not to remove the fan blades because it will upset the balance of the fan. Believe me, adding the magnets to the fan upsets the balance a whole lot more than removing the blades ever could - it will still be fine.
Removing the blades gave me so much room inside that I was able to use the fan frame as the case of the device - I just added a top and a bottom.
Only use a fan that will run off around 5v.
Many 12v pc fans will not turn at lower voltages, and this means that running off a lower voltage to slow it down (or using a potentiometer) won't work.
I had four old fans to choose from and only one of them would run at anything less than 12v.
The one that did work runs fine from a 5v usb wall wart.
This is the most important one: place your beaker on the stirrer with the stir bar in it, and then turn on the power.
Even at 5v, mine still runs too fast to capture the stir bar if it is already running when I place the breaker on it.
Starting it up after putting the beaker/stir bar on it gives the stir bar time to 'catch up' with the magnet.
Oh, and if you're using a hard drive magnet, use two, one stacked on top of the other.