To Cost

1. To incur a charge of; to require payment of a (specified) price.
2. To cause something to be lost; to cause the expenditure or relinquishment of.
3. To require to be borne or suffered; to cause.
4. To calculate or estimate a price.

The past tense and past participle is cost in the sense of "this computer cost me £600", but costed in the sense of 'calculated', "the project was costed at $1 million."