suggestions of affordable clothes for beginner rides?
For a beginner, as long as all the required naughty bits are covered, and you're comfortable standing and walking in those clothes, then they're generally fine for cycling.

A beginner is anyone tootling 3 kilometres/2 miles each way.  If you're regularly doing rides of 16 km/10 miles then that's about where cycling clothing will come in handy.

There's no need to go silly with race gear.  

The first specialist items to consider are


Padded pants or shorts or bibs  like http://www.dx.com/p/top-cycling-cycling-silicone-cushion-underpants-for-men-black-l-258557#.VnPkpW_4ugo for $10 US or bibs like  http://www.dx.com/p/2012-bike-bicycle-cycling-padded-bib-shorts-black-size-xl-125561#.VnPioW_4ugo   You're after something between your backside and the seat, and ideally pants to give some compression on your knees.  
High visibility top (NOT BLACK!) like http://www.dx.com/s/NJ600  Under $20 US  or http://www.dx.com/p/spakct-stylish-sleeveless-cycling-jersey-t-shirt-fluorescence-green-l-227832#.VnPknG_4ugo 
Gloves, I just wear $2 white gardening gloves from the local hardware shop.


I have bought all these things and they work fine for me.  My longest ride was last weekend were I did 118 km.

Other than that, check this site for "what tools to carry on a ride" and nutrition/hydration questions.  However that's bike gear not clothing so only a brief reference.