Easy witchcraft supplies are probably all around you, and it isn't that hard to put an altar together. You don't really have to get a big collection of complicated or fancy pieces if you don't want to (or can't afford to).
Sure, it can be nice to have a gorgeous table filled with custom-made items but it isn't an actual necessity in order to make some magick. Rather than do without, here are a few suggestions for easy witchcraft supplies that anyone can find.
Candles - Well, this shouldn't be too hard. You don't need anything fancy. Dollar store candles will work just fine, and they often come in a range of colors to suit your purposes.
Herbs - Yes, some herbs are going to be harder to find than others, but don't forget about your pantry when putting spells together. Basil, cinnamon, pepper, ginger, vanilla, sage and dill are easy enough to find and have several potential uses.
Chalice - Any glass will do and you could probably spring for a nice stemmed wine glass at the local thrift shop. Any material is really fine as long as you stay away from plastic.
Athame - While a nice kitchen knife would do, you can also go with a decorative letter opener as your athame.
Cauldron - Any heat-proof dish can be used. To be honest, it's not the most practical tool out there, and you could probably skip it if you can't find something suitable.
Wand - Get a stick from outside and clean it up. Possibly the easiest witchcraft tool you'll ever find.
Crystals - This is a bit tougher. If you don't have any way to get a little collection of stones, try to find a good piece of clear quartz. You can use that as a replacement for other stones. It won't be as attuned to your purpose as the correct crystal, but it will work very well. Other than that, try to get stones at craft or garden stores. You'll be surprised when they may carry.
Miscellaneous - Besides the usual tools, there are always other supplies you come across. Yarn or ribbon, paper and fabric are all found at the dollar store and shouldn't be too much of a challenge. Frankly, easy witchcraft supplies can be found all around you as long as you don't get all hung up on having to buy stuff at "official" occult shops.
One other benefit of these types of witchcraft tools is that they are much easier to hide if you aren't being open about your spiritual practices at home.