Now one of the most important things in working in agar is the right instruments. You will need a good pair of tweezers, a set of scalpels, disposable are ok but you want a triangular tip. You should certainly have a spore loop - it is a nichrome wire twisted on itself to make a tiny loop and the wire inserted into a handle. You can also get plastic, disposable "bac loops" if you don't intend to do lots of spore work - they are pretty damn cheap though. I also like a heavier scalpel that isn't so sharp but will easily cut agar - Look for wax carving tools or dental instruments. You will be scooping, slicing and picking bits of agar with mycelium attached.
Now you will also need some sort of device to sterilize your instruments ongoingly in your glove box, LAFH or just in a still room. Now you can use an alcohol lamp but I find them slow and cumbersom. I prefer a torch. The one I use is a micro nitrous/butane torch that gives me a 2500+ degree pencil tip flame. This ensures that I can heat the tip of my instrument to red hot in a second and the heat does not travel up the handle. However, you do not need this. Any torch will do nicely and in fact, you don't have to torch your instruments at all.
If you get a double set of all of your instruments you can use 91 percent isopropal or denatured alcohol and swap instruments. One instrument is immersed in the sterilizing agent while you work with the other - this works well but only if you have cleaned and autoclaved your instruments beforehand (wrap your instruments in aluminum foil and pressure cook them for 40 minutes).
Find yourself a half liter or liter glass container that has a smallish opening, about anything you can find will work, I use an erlenmyer 1 liter when working with 500 mil amounts.
finally, you are going to have to get yourself some petri dishes. I like disposable but glass would work better for you if you are uncertain of the conditions you are working with. You see, you will have to steriize your agar and then pour it individualy into your plastic dishes - this invites contamination as you pour. With glass, you can prefill your dishes and sterilize the agar and dish at the same time. Up to you. if you don't do a lot of work, plastic is better, if you want to save money, get glass but you will have to wash them. You will rarely need anything but 90 X 15 or 100 X 15 but the 150's are useful for multiple mating and the 50's are just cool.
Finally you might want to get yourself some micropore tape. It is used to seal the sides of the petri dishes against contamination while still allowing air into the dish. I use this stuff for micropropagation work but have never found it necessary for mushroom work. Because the micropropagation stuff uses sucrose, it invites mites and the micropore tape is somewhat of a barrier (not completely though - damn it).
It is surprising that if you do not expose your dishes to breeze, most spores or dust (most spores adhere to dust and dust motes rather than just floating around all by themselves) will not get under the dish. When that does happen though you will almost always see that the contamination remains very close to the edge of the dish - usually this means that you can quickly scoop it away before it begins to sporulate. This is the ONLY time you want to consider taking the contamination away from the plate - in all other situations you will be taking the myclium away instead - but more about that later.
Eventually, something may get into your dish. When this something gets in after your mycelium has reached the edge of the plate, the spore will not germinate - yet. It will rest upon the mat of myclium and wait until you transfer the mycelium to new substrate and then it will grow and you will never be able to stop it -
The way to guard against this is by using the micropore tape.