If you want to send something abroad here are a few things I've picked up.
1. Search for other charities working in the area you want to ship to. If they are sending out a container you may be able to piggy back your items in their load or share costs.
2. Sometimes the company you are buying the equipment from will arrange shipping for you. Ask them to supply a quote for the shipping and a quote for just delivery to the airport/shipping agency. Find out the weight and size of the packed boxes/container and phone/email around for quotes. We managed to save £1,000 of the cost of shipping this way by choosing a smaller airline.
3. If you are quoted 6 weeks that is just the travelling time - there will generally be a 2 week delay before shipping actually happens and a 6 week delay getting through customs.
4. If you are sending something inland check the costs of inland travel before making your final decision - air freight may be cheaper once land freight costs have been factored in.
5. Customs always takes longer than you expect. A lot longer. Don't plan a trip to coincide with the arrival of some equipment until you know it has arrived and cleared customs.
6. Find someone on the ground who knows the import regulations, maybe a shipping agency and get whatever advice help you can get before sending the container. Sometimes a piece of paper from a government agency stating the items are being sent for charitable purposes (even if you are not a registered charity) will mean the difference between paying customs duty and not paying. It is possisble to get this sort of paperwork once the container has arrived but you may have to pay storage fees if the container sits in customs too long and this could end up more than the customs charge.
7. Find out what the correct customs charge should be. If you are asked to pay an unreasanable customs charge (sometimes called a bribe or tribute) - argue. Try and speak to different customs officials or government ministers for anti-corruption. Threaten to ship the items back to England if neccessary. Try and drive home the message that corruption harms the country and stops foreigners wanting to invest their time and money in their country. We saved £3,000 this way.
If this will make you over your baggage allowance phone the airport first and try and negotiate a higher baggage allowance first. Try and negotiate a lower excess baggage rate.
On 1 trip (Air France) we were 15kg overweight and were charged £255
The next time we phoned first (Air Mauritus) and negotiated - some items were discounted from the total weight (guitar and amplifier), we were offered a business class weight allowance instead of economy and given a special excess baggae rate for what was left. In total we had 65kg excess baggage and were only charged £50.
If that fails - ask them if you can send the items as cargo on the plane you are going on. This usually involves a trip to the airport the day before or a few hours before you need to be there. Cargo rates are cheaper than excess baggage.