Pull Down boxes and Tables

OK, thanks to you guys I am nearly done with my project. Here goes the last part. I have a list of items in a drop down box, about 8 of them and they each have a different daily, weekly and monthly rate. Normally 3 days is the same cost as a week, and 3 weeks is the same as a month. Now thanks to you guys I have a table of about 7 cells that all I do is input the man hours, and it gives me how many months, weeks and days of rental charge there will be. How do I make it so a cell will reference the drop down box, use the correct price info for that particular equipment, the hours another cell says are needed and use the month/week/day calculater to make the right price. I have 2 cells open horizontal to each other if that helps. I was thinking maybe a different chart for each equipment using =sumproduct, but im not sure if that can be done, or if there is an easier way. Again, any help is GREATLY apreciated. Thanks in advance.

ps ill give an example. shovel cost- $30/day $90/week $270/month
hole digging will take 215 hours, so I need the shovel for 1 month, 1 week and 2 days. so the cost will be 270 + 90+ 60 = $420

LOL, I was just throwing numbers out there to illustrate the pricing pattern.

Ok here is what I came up with. It seems kinda sloppy, and ill have to do a month/week/day calulater for every row (about 100) but that was the easiest way I could figure it out. Is there a way to make the calculater one cell maybe? I dont know, but any help awesome, my brain is fried. Ill check back tomorrow.BTW thanks for the help Pjaoquin, you are awesome man.