Venue: You can look at public parks ( I took the location and season into account). you should only have to pay for a use permit. However, your guest count is a bit high for something like this. See if any of your family/friends are members at a private club and if they can get you a discount.
Food/Alcohol: Check your local culinary schools. 9 times out of 10 there is a teacher that does catering on the side or the school operates a catering business off-site. Yes, there is the chance that the food may not be exactly what you are looking for, but it is likely to be decent quality. Alcohol should be bought by you in quantity at someplace like Total Wine or Costco or something and then just hire barbacks. (Check the culinary school for those as well)
Photography: Here, I say spend the money. If you don't want to, leave disposable cameras at every table and hope your guests use them and leave them for you to get developed.
Music: If you are at all technologically advanced, make a 4 hr playlist on your Ipod and make sure to rent speakers to fill the room. Hook the speakers up to your Ipod dock and have at it!
Not mentioned, but I have an opinion:
Flowers: Check out local nurseries and see what is in season and if they have any "classes" for bouquet making.
Dress: Consignment shops are your friend. Find a great dress ( doesn't even have to be a traditional wedding dress) and get it altered if need be.
Have a wonderful day!