The cost of replacement of parts is variable. A locally made motherboard will not do justice to your Dell laptop. If parts are exported or are obtained from the company, then the price can go up. If you have a more expensive processor or brand of the laptop, then the parts will also be quite expensive. The technicians will use the best quality and give you a warranty on the replacement. It will come at fixed prices. If you are willing to use a cheaper substitute, then notify the expert who may suggest a suitable alternative. It is always advisable to use genuine products over more affordable options. In that case, the professional may not be able to provide you with a guarantee even though your problem can get resolved.