Because it's handmade, of course designer handmade jewelry will be more expensive than that which you can get from mass market outlets. That's only fair. Even if a piece of jewelry is made from inexpensive materials, if its handmade, that means its artisan spent hours and hours designing and crafting that piece, putting love into it, much different than the mass market material churned out by soulless machines.
Indeed, designer handmade jewelry can vary in price simply because of the types of material used to create it. A piece of jewelry crafted together of seashells or beans, for example, will consist of many man-hours of intensive handwork. Other pieces, using precious metals or precious stones, will take just as much time but will be subsequently more expensive.
Make sure that you care for your jewelry. Silver jewelry will tarnish over time. Fortunately, there are plenty of commercial products that will enable you to polish the jewelry to remove that dark stain. However, you want to be careful when you're polishing, because you do not want to remove the piece's own natural patina, which makes silver so special...and so valuable.
Of course you won't need to polish your silver if you prevent the formation of tarnish first. And of course, there are commercial products for sale that will prevent this.
If you've spent a considerable sum on your designer handmade jewelry, it behooves you to care for it properly.