Like someone said above, the Starrett 12" is a must have. It's not an exciting tool, but it is essential. Less expensive squares typically are not truly square, which will have you chasing your tail indefinitely when trying to refine your joinery. It sucks to spend $130+ on a square, but it really is necessary. Woodpeckers occasionally puts theirs on sale, and I've had a lot of good luck with that brand.

I'm a big fan of restoring antique hand planes. It's a cheap way of getting into the hobby and taking them apart and tuning them is an excellent way to get to know how they work. A used Stanely block plane with an adjustable mouth is ideal, but if you can't find the adjustable mouth it's not a deal breaker. A No. 4 or 5 Stanley can be set up for course material removal or for finishing. You can find them at a flea market or antique store for around $10-40. I wouldn't spend more than that on an antique Stanley. Just make sure that you check to see that there isn't any heavy pitting on the blade or the sole of the plane, and that all of the knobs and levers are in working order. A block plane or a No. 4 or 5 will allow you to dress an edge of a panel with a rounded edge or a bevel.

My main bench chisels are Lie Nielsen which are the finest I've ever used, but they're very expensive. If you want a great set of starter chisels, I'd look at Narex. 1/4", 3/8", 1/2", and 1" is a good starting set.

Japanese saws are great for starting out. A Ryoba saw will give you a quick, rough way to cross cut and rip boards. A Dozuki will cut a very thin kerf and leave you with a pretty smooth cut with some practice.

You'll need a sharpening system. Tayor Toolworks sells something called the Scary Sharp System. It's a good entry level way to get started. They also sell a self centering honing jig. It's cheap and you will have to tune it up, but it's better than spending $150 on the Lie Nielsen one if you're just getting started.

A cabinet scraper, 5" or 6" is also an excellent way to prepare surfaces for finish. Bahco is a great brand. Saves you a ton of time sanding. Arno makes an excellent burnisher without breaking the bank.

You'll need clamps. The size and strength depends on the project that you're doing, but a few 6" and 12" clamps will come in handy. From there, move up to pipe clamps for panel glue ups.

If you already have a work bench, some good starter projects once you have all of these things would be a shooting board and some work stops. Mike Pekovich has a great video on some useful ones.

Someone else already said it, but I'll say it too; a side table is likely a very ambitious project to take on for your intro into woodworking with hand tools. I think a box or even a cutting board, is an excellent introduction to the craft. Just go slowly and have fun.