Spoties aren't battery snobs. You can stick any silver oxide battery that fits the battery. Other then shorter life I'm not sure why you couldn't fit an alkaline battery. The meter is designed well enough to handle non-standard batteries.
Off the top of my head I don't remember the battery that fits perfectly. I want to say a 387 or 400 watch battery. When I was looking I had no lucky finding either in Toronto. The battery shop that Radio Shack runs had a smaller battery in a little rubber ring. Kind of expensive for just a little rubber washer.
The real bargain lenses tend to be the 135mm. Basically ignored by many but very common. Pentax made good ones. So did Mamiya. I've got a real nice Mamiya 135mm. You can also get various Soviet M42 lenses.