What type of diving do you plan on doing? Warm water only, or locally? You only asked about basic goods, so I am assuming you mean soft goods. Mask, snorkel, fins, boots but...
I'm going to have to disagree slightly with D&K. A reg is your most important piece. I don't know if you are interested in buying hard goods yet, but don't get a regulator until you can buy a "class a". I would also recommend getting a sealed reg. That way over time none of the water gets in your internals. (Having a piece of sand get stuck in your diaphram sucks!)
The part I will agree with, if you don't get a decent suit, you aren't going to go locally. The cold will just keep you away. You might want to just take a drysuit class and rent one until you can save up for it. Warm in CA is 60's. If it is that warm, you'll have 2 foot vis from the plankton bloom. The best CA diving is 50ish degrees and that requires a drysuit for normal people.