All breast implants come with risks and complications. You should expect to need additional surgeries in the future no matter what type of implants you get.
For example, all breast implants will eventually break or leak. When saline implants break, they usually deflate quickly. The salt water is usually not dangerous, but most women will not want to have a deflated breast that is much smaller than the augmented breast. When silicone implants leak, it is not always noticeable, but it can cause pain, swelling, or allergic and/or autoimmune reactions. If you get silicone implants, you will need periodic and expensive MRIs to check for ruptures in order to avoid those health problems.
It is important to know that all breast implants (saline and silicone) can cause anaplastic large cell lymphoma, a cancer of the immune system.
Breast implant surgery usually costs between $5000 and $8000. Silicone implants usually cost about $1000 more than saline implants. However, you should expect to spend much more on future complications and/or additional surgeries.