Choose a big, cheap tent for BC. You will need the space and privacy, especially if joining a large expedition.
There should also be tents at C1, C2, C3 and C4. The C1 tent can double as C3 or C4 tent since you will climb BC to C2 in one go when acclimatized.
You will need high quality tents at all high camps. North Face, Marmot and Mountain Hardware are the dominating brands.
Call the agent in your area and ask for a good price. Getting gear for free is difficult since these people are trying to make a living out of it, but buying at wholesale price should be easy in return for a picture or so.The agents, often high altitude climbers themselves, are also a great source of information about new materials.
They need to be Down with at least 1000 grams/35 ounce of filling. Don't go cheap with sleeping bags. You will need two or three of them. One of them can be lighter (for the trek and also for BC later in the season).
Within just a couple of days, the bag will absorb up to one kilo (2 pound) of your perspiration, this affecting both it's power of insulation and your load.
Allow the bag to dry up on top of your tent every sunny day. Secure the bag with rock.
Get a set for each camp. You need double layers in BC and C2 to protect you from the rocks. If you feel cold easily, you might need double layers for the other camps as well. ThermaRest works great together with RidgeRest or the like. No crampons in tent, they'll puncture the Therma.
Get a C2 cook, or - if in a small expedition - share one with other people. That will make both you and the sherpas much happier. Past expedition we spent 30 days above BC. Tendi, our C2 cook, really helped the sherpas and us to stay in good health. We actually preferred C2 to BC!
For the high camps, carry 2 small Titanium burners. Working two stoves when you are tired really makes a difference. Your cooking time will take half the time, allowing you more rest.
Bring two light pots with lids for C1, those ultimately proceeding to C3 and C4. You could also bring a spare to keep at C3. You need a spoon to eat. Keep a good knife (Leatherman works great) in your pack at all times. Plastic mugs. Don't forget potholders. These tend to disappear too, so bring two for camp.
Bring plenty of matches and lighters. Beware, last year we bought 30 lighters in Kathmandu, none worked higher than BC and we still have no clue why! Get the sherpas to shop for the good ones or bring from home.
We used Swedish liquid water purification called Aqua Care,www.aquacare.se.
It has absolutely no taste and is highly efficient. Put a few drops in cold water and you can drink almost anything. No need to boil all water has really helped us to cut down on gas. The snow around camps is often contaminated with human feces and should always be carefully checked and purified. Pour the Aqua care into everything, and make sure that the cooking staff has water bowls with desinfectant in it outside the cooking tent to wash their hands after visits to the bathroom.
Order gas through your trekking agency. If you have a C2 cook you will need about 20-30 normal size cans for your personal climb. The cost is US 7-10 per container.
The trekking agency will provide a large gas container for the C2 cooking tent.