First of all, your budget will have a great impact on where and how you obtain your materials and pieces for your outfits.
If you have the tools (i.e. time, cutting mat and rotary blade, sewing machine, etc for making a doctors coat) then I would highly suggest taking the time to go to a Joanns or similar type fabric store, browse their patterns section, find patterns that you like and narrow it down to the design you like, then looking for how much fabric it calls for and get it.
Keep in mind that you can use your measurements (if you feel comfortable) to tailor the outfit to be more form fitting if that is your desire. You can use newpapers and tracing skill to edit and make your own pattern based off of the premade pattern you selected and your measurements.
Making your own outfit will save you money in the fact that you aren't paying labor fees for someone else to build it, however it will take more of your time and much more effort to pull it off. But keep in mind that there is a great deal of satisfaction in learning throughout the process and coming out the other side with a piece that is one of a kind and you can say you made yourself. It's a great feeling.
That isn't to say that you can't outsource pieces that you don't have the tools to make (leatherworking, armor pieces, shoes, etc). There are some great small businesses that depend on niche consumers like us to keep them afloat and have unique and awesome talent!
If you wade through all of the copy cats on Etsy you can find some gems. Here are a few that I have utilized, and others that have merely caught my eye that you may find useful:
For unique belts/leatherworking:
KRadwear - https://www.etsy.com/shop/Kradwear
ScandaloAlSole - https://www.etsy.com/shop/ScandaloAlSole
WJWDesign - https://www.etsy.com/shop/WJWDesign
For unique clothing/shoes:
HoreHead - https://www.etsy.com/shop/HoreHead
Punkktual - https://www.etsy.com/shop/Punkktual
Runnickyrun - https://www.etsy.com/shop/runnickyrun
Dracolite - https://www.etsy.com/shop/Dracolite
Ayyawear/Verillas - Ayyawear.com / Verillas.com
Helmets/Masks:
TomBanwell - https://www.etsy.com/shop/TomBanwell
HeadShotProps - https://www.etsy.com/shop/HeadShotProps
Oldjunkyardboutique - https://www.etsy.com/shop/oldjunkyardboutique
NokturnelEclipse - https://www.etsy.com/shop/NokturnelEclipse
Needless to say there are a lot of places out there, and there are going to be a few that are right in your budget range.
I would highly suggest browsing the various lightsaber forums and SW cosplay forums - they all have very detailed and extensive tutorials and knowledge on how to make anything you need - many are budget builds, ways that people have found to save money - others are kind hobbyists who offer their services in areas you may not feel comfortable dabbling in or don't have the tools for - for example clothiers, armorers, leatherworkers, etc.
Linked here is an example of a detailed thread with links to tutorials and makers for Female Beskar'gam: http://mercs.firespray.net/forum/index.php?topic=70240.0
And here is a link to a detailed thread of makers for costumes and SW costumes in general: http://www.saberforum.com/index.php?topic=11068.0
I've basically done all of the searching around for just the bare bones of what you're asking, but don't be afraid to browse and research and discover - that's how I've come across all of the information I've linked to you.
Enjoy the creative process and check out how others have been so successful at cosplay!
I've made my own cosplay basically from scratch, sewing and also utilizing skilled makers for the items I can't make myself. So if you have any more specific questions, I can try and answer them or others on the forum may be able to assist you as well.
Good luck and happy creating!
Aletani