I read the 4 WAN-port modem is USD 400. But you can sell 1 of your routers to limit the financial damage.
I have a two broadband (Indian standards) connections that I want to use together. One is a 1mbps and the other is a 512kbps. The config that I have is below.
OS: Windows 7
Laptop: Acer Aspire
Router 1: Buffalo AirStation WHR-G54S
Router 2: ZyXEL P-600
I read about it on a few boards but I couldn't find any proper info on that.
This all depends what you mean using them together.
You could for example open one web page on one connection and open a different web page on another.
You will not be able to stream data faster from say utube or netflix. You could download 2 different video feeds faster but not a single one.
The key reason that sharing is not possible with just simple modems is you have 2 ip addresses. How does a server know that 2 different IP are the same person and not 2 different ones. The whole concept of a session is based on the theory that a user will only have a single IP. The server would have to have special applications to allow this.
The only way this is even done is to send all the data from both modem to a single ISP or external company who would then combine them together. It still has issues in some application since the data does not really transfer at the same speed on the 2 connections so you could get packets out of order. This is critical for some applications.
You are more than likely better off just buying a faster connection from the ISP, it will be cheaper than paying for a service to combine the links.
Now if you just want to manually control which link is used for which sites you can use the ROUTE command in your PC but it only works as well your ability to predict your traffic loads.