Inspiron 15 3000 series laptop

I don't have that laptop, but according to the specs at the Dell site, it has an HDMI port and a USB3 port (and two USB2 ports). So there are two ways for you to go:

(1) Utilize the HDMI port. Get an HDMI-to-VGA adapter. Here's an example:
http://www.amazon.com/StarTech-com-HD2VGAE2-Converter-Desktop-Ultrabooks/dp/B00BUKO6CW/

Same thing, but this one also supports audio:
http://www.amazon.com/StarTech-com-HD2VGAA2-Converter-Desktop-Ultrabook/dp/B00BUKO4WY/

(2) Utilize the USB3 port. Get a USB3 to VGA external video card. Here's an example:
http://www.amazon.com/StarTech-com-External-Monitor-1920x1200-USB32VGAES/dp/B00H91BRZU/

Although there are USB2 devices, I prefer using USB3 speed for good video, and since your laptop has a USB3 port, you may as well take advantage of it.

I recommended those items because I use many StarTech products and am very happy with them. I don't have the items above, but due to my excellent results with many StarTech products, I wouldn't hesitate to buy these.

That said, there are many other similar products. Searches at Amazon for "hdmi to vga" and "usb3 to vga" will give you plenty to choose from, such as:

http://www.amazon.com/Generic-Adapter-Converter-Laptop-NoteBook/dp/B007PLL4CK/
http://www.amazon.com/PETHV-converter-3-5mm-Stereo-Converter/dp/B003O55U8K/
http://www.amazon.com/Cable-Matters%C2%AE-SuperSpeed-Adapter-Windows/dp/B00IU1V9CO/
http://www.amazon.com/LinkS-SuperSpeed-USB-Adapter-Windows/dp/B00NYZE3VK/

Regards, Joe