For the long exposures of a pinhole camera, I would recommend Fuji Neopan 100 Acros or Kodak T-Max 100 for black and white films. They are among the fastest films out there for long exposures.
For transparency films, I would try Fujichrome Provia, T64, or Astia.
For an all-around beginning film (not just for pinhole cameras), I would recommend Tri-X or HP5 for fast films and Plus-X or FP4 for medium films.
At this point in time, Arista Premium is by far the best choice IMO, for beginners or anyone else. It is exactly the same as Kodak Plus-X and Tri-X as far as I can tell, but it is half the price, and cheaper than most of the "bargain" films out there, making it the best quality:dollar ratio available in a 35mm b/w film.
For beginner chemicals, I recommend Kodak HC-110 or Ilford Ilfotec HC. They are convenient, quick, consistent, versatile, and they last forever as concentrate (and for a very long time as stock). I would recommend Ilford Hypam or Ilford Rapid Fixer over Kodafix, as the Ilford ones do not have hardeners, which are unnecessary (and not recommended) for modern high-quality films. Both of these are liquid concentrates, which I love. They can be mixed at room temperature, and do not require the handling of any powders.
A cheap bottle of indicator stop bath will last you years. I filter and reuse my stop bath until it goes purple. I have had my current 16 oz. $7.00 bottle of Kodak Indicator Stop bath for about 3-1/2 years, and I have used 1/3 of it. Doesn't make much sense to improvise a stop bath at the rate of under a dollar per year! If you are going to cut corners on chemical costs, don't bother doing it with stop bath, IMO. Do it by purchasing your own powders and a scale.