can i buy and ship a 2001 mazda mp to nigeria for 4,000dollar
No, or unlikely. I don't know the shipping cost but you will have to pay almost that just to buy the car, and shipping to Nigeria can not be cheap.
I did a little research and shipping will run anywhere from $1,500, (the cheapest I found) all the way up to $4,000, depending on many things, from where in the US, container vs. roll-on-roll-off, and many other things. Plus you might want to consider insurance on the shipping, obscenely expensive, upwards of $500