I have a big forehead. What are my options?

Forehead reduction surgery or hair grafting transplant can both lower your hairline.  It would be in your interest to have a consultation with a doctor and understand your risks and benefits of each surgery.  It would not be fair to suggest one or the other option without an examination or understanding your specific goals. There are issues of scarring, shock hair loss, hairline shape, and many other factors that must be understood.
First, you need to meet with a doctor so you can explain your goals and expectations.  Afterwards, you'll have a better idea as to how much your procedure may cost.  Sometimes your goals may be unachievable and you may be turned down by our doctor.

Forehead reduction/hairline lowering is probably the best option. The results are immediate and maintains your hair density. There is a long incision which is hidden in the hair and is hard to see after it heals. 

I feel the Irregular Trichophytic Hairline Incision technique that I described many years ago is the best procedure to reduce the forehead in most patients because the results are immediate,and normal uniform density and distribution of the hair is maintained.

There are two types of procedures for lowering a hairline. One is a surgical excision of the upper forehead followed by the downward advancement of the hairline up to an inch from where it was prior to the surgery. To accomplish this, the entire scalp from the frontal hairline to the very back of the crown is lifted up and pulled forward. When this is done by an experienced surgeon, the hairline can often be advanced about 2/3rd – 1 inch if there is enough looseness when this lifting process is done. This procedure is often complete in one surgical session; however, it may not address receded corners of the hairline if the corner recession is significant. A great advantage of this surgical approach is the immediate impact of the procedure on hairline location with healing usually complete in a week or so. Sometimes this procedure produces a scar in front of the hairline, and if this is this is the case, a hair transplant in front of the hairline can address the scar. If there is corner hair loss or if you are a male, a hair transplant lowering surgery is better because of the risk of recession in men with genetic balding is very high. A recession will always reveal the scar from a hairline advancement surgery. The only disadvantage to the transplant is that it takes 6-8 months to fully grow out. For men, a hair transplant is a better procedure because of the risk of hair loss is high and hairline recession will show the scar from a hairline advancement surgery.

The second type of hairline lower procedure is done through hair transplantation. The number of sessions varies by the thickness of the hair. For women with other than fine hair, they might do this in a single session. With finer hair, it often takes two sessions. The time to see the impact of a hairline lowering hair transplant procedure is 7-8 months and if a second session is required, it will take another 7-8 month to wait for full growth. See web-references below for four excellent sets of photos of this process on four women. When done properly, a transition zone is created that makes the frontal leading edge of the hairline soft and what I call a no-hairline hairline.