Things to think about
1- What kind of springs are in your fork tubes? Has the previous owner changed them from the OEM progressive style, or has he installed "straight" springs?
2- If new springs have been installed, what is their weight? You can check this if there is written documentation that the previous owner provided or, place the bike on its centerstand, jack the front end off of the floor, (do you have a skidplate?), remove all preload on the springs, remove fork caps, fish any washers, spacers and springs out of the fork tube. Often there is a mark etched on one end of the spring that will tell you the weight of the spring.
3- Next, you will want to weigh yourself with all of your gear on. Also weigh your luggage and make a decent estimate on the weight of extras that have been added to the motorcycle; luggage racks, cases, skidplate, crashbars, etc.
4- Determine the predominate type of riding you do, (what type of surfaces), and at what level you feel comfortable riding.
5- Armed with the above information, you can head to any spring dealer and properly match a front end suspension system specifically to you.
I like Sonic Springs
. They are a straight wound spring.
Here is a link to their spring rate calculator: Spring Rate Calculator
Here is a link to Sonic's Tech articles: Tech Articles
Your cheapest route is to determine what is currently in your forks now and to see if it matches to your weight and riding style. What's there may be right on and you needn't spend a nickel more.
From there, new springs and oil matched to your weight will cost you about $100 if you do the work yourself. There is a tutorial in the "How To" section of this forum.
I recommend adding a forkbrace at some point. Prices vary as to which manufacturer you choose. I have a Superbrace installed on my bike. I believe it cost me about $150. Worth it!!!!
You could also add Gold Valve emulators which will also cost you about $150 if you do the work yourself. Some riders love them. For the riding I do, I wish I didn't spend the money on them.
For a rear shock, you may want to look at Hyperpro
. I have a Hyperpro #460 installed in my bike. It is a very good quality shock with a 5 year warranty. It is basic and simple. No "do-dads" that can cost a fortune. The shock cost me $614 with shipping. I installed it myself. There is a tutorial on how to do this in the "How To" section.
Hope this helps.