I am trying to construct an easy RSS widget (for my wordpress blog) which will show a listing of stocks, or marketplaces, as well as their current prices.

I cant appear to locate an API with this data anywhere - can anybody suggest this type of factor (possibly being an Feed?)

Yahoo come with an (undocumented) Stock Quotes API in their Finance API

Essentially, http://download.finance.yahoo.com/d/quotes.csv?s=GOOG&f=ll will return the cost for GOOG stock in Resumes format

The s parameter may be the stock symbol. You are able to specify multiple by separating all of them with +

quotes.csv?s=GOOG+YHOO‎

The f parameter may be the data format code, that we found recorded from this Python script (also is the way i discovered the API..):

code   description

l1     cost

c1     change

v      volume

a2     avg_daily_volume

x      stock_exchange

j1     market_cap

b4     book_value

j4     ebitda

d      dividend_per_share

y      dividend_yield

e      earnings_per_share

k      52_week_high

j      52_week_low

m3     50day_moving_avg

m4     200day_moving_avg

r      cost_earnings_ratio

r5     cost_earnings_growth_ratio

p5     cost_sales_ratio

p6     cost_book_ratio

s7     short_ratio

They all are recorded on this site

The information is came back like a comma separated file, that ought to be absolutely trivial to parse in a language

You may also use Google's Finance API to obtain Stock Quotes inside a slightly round-a-bout way

Essentially you produce a Google Spreadsheet, and employ the GoogleFinance function:

=GoogleFinance("GOOG" "cost")

..then make use of the Spreadsheet API to gain access to that value

I discovered this via "Presenting the Google Finance API", and "Tips to get a real-time stock quote using Google API" describes this really is more detail, together with a simple party spend-script to gain access to the information (It might be simplified by looking into making the spreadsheet openly accessible)

your real question is not obvious however, you may try http://world wide web.smartmoney.com/rss/ or http://world wide web.quoterss.com/ basically understand you right

There's also the Google Stock API. And you will use Yahoo's YQL to find the data in XML or JSON formats: Yahoo Stock API via YQL.

Should you simply want just one stock the Google you might most likely perform best. For multiple, or even more complex data like EBIT I'd make use of the Yahoo one.