What is a good thing I can invest in to earn big profit? about 250,000?

If you don't want to deal in drugs, why not just buy a gun??

Mutual funds- Go to your bank.

drug dealing

GBPUSD: The pair closed higher on Monday leaving risk higher in the days ahead. On the downside, support lies at the 1.200 level where a break will turn attention to the 1.2400 level. Further down, support lies at the 1.200 level. Below here will set the stage for more weakness towards the 1.2300 level. Conversely, resistance stands at the 1.200 levels with a turn above here allowing more strength to build up towards the 1.2600 level. Further out, resistance resides at the 1.200 level followed by the 1.200 level. On the whole, GBPUSD threatens further weakness on correction.

How much do you have to invest? how long until you want to reach your goal (10 years, 20 years?, etc.)

8 pounds of gold would give you a good start