Reddit mentions of Nuby 8-Pack Play Links

The thing with cosplay is you have to choose whether to go recognizable or not. In some geek circles (like Star Trek) people go out of their way to be obscure characters. Since you're looking at a screening, you could go a bit off the path, but I still doubt there are that many hardcore fans out there (yet?) who know every sigil. For that reason you may want to stuck to more obvious identifiers.

If you go with a House (my recommendation for price and ease), you could make a cheap and comfortable costume based around a tabard. For that you only need some cloth remnants (you can get them cheap from any store that sells fabric) and compatible street clothes. Wear boots of some kind, pants-that-aren't-jeans, and a long-sleeve shirt that ideally is in the right color scheme of your chosen House. If your boots don't look right and/or you can't lace them over your pants, you can use a cloth remnant to wrap around the bottom of your pants, around the boots and just X-lace it to your leg using another strip of cloth. The same trick can be used on your forearms if your sleeves don't look that great. When it's done in matching colors it can look really good for something so simple.

The key to this though is the tabard that'll cover up the rest of the street clothes. It's the only piece requiring real crafting skills. Make a tabard from the cloth remnants; you can cut out a sigil design for the front of it and just sew it. It can be as nice as you want to make it, like contrast-color borders, or a quartered pattern, etc. I just googled up this guide. I'm sure there are many, many more online.

For accent you can belt it with any wide leather belt. If you can get your hands on (or make) a leather ring belt you'll look even better. Any knife/dagger/sword can help complete the look, though a long blade is usually not that comfortable to deal with when sitting in modern public settings. If you do have leather availability, a simply set of vambraces can also cover the ends of your sleeves and look nice.

The beauty of that is the ability to take it off and be wearing street clothes very easily.

Oh and another thought I had a bit ago for cosplay on the cheap, if you want to go the Maester route. These link toys (another example) are in every generic store, Target, Wal-Mart, etc., for next to nothing. They are very lightweight, come in different shapes, and are easy to link to whatever length of chain you want with whatever color combination. They're a little big, but it's hard to beat the price, and an exaggerated chain would help with cosplay identification. The plastic also should take spraypaint very easily if you want a shiny metallic look. The main drawback to Maester though is the robes. Even if you can find or make them, robes can be heavy, bulky, and hot, so fair warning.