One of the easiest ways to house your piggy is to use wire cube storage. These are available from many stores; Wal-Mart, Target, etc. They do vary slightly in size and diameter of the wire, so be sure to pick a size that can be "mated with" later. A bare minimum of 2x2 cube faces should be used.
Coroplast [also known as Polyflute, FlutePlast, IntePro, Proplex, Correx, Twinplast, Corriflute or Corflute] can be used to make clean, durable sleeping quarters, etc. We get ours at LOCAL (not chain) sign suppliers. The cost price of these are <$11 per sheet. It comes in 4'x8' sheets, so you will have problems getting it into a ''normal'' car without rolling it. It fitted into our (at the time) Audi A3 TDI Sportback easily.
Caution! The price of a sheet varies enourmously, depending on whether the sign maker wants to be bothered in dealing with you. Our nearest store wanted a massive $48 a sheet(!), yet yards away it was <$11.
Bedding - The best is VetBed and can be bought from the UK for much, much less than the cost per square foot in the USA. Please visit Discount Pet Beds on eBay. Order the white with green backing. This shows any traces of blood easily and the backing works (seemingly) better than others. Order more than you need, so that you have some later and get the best out of your shipping costs. It is very hard wearing and can be machine washed many hundreds of times. If you still have spare, pass it on to your friends with a comment about it's source.
Currently our girls are on custom fleece pads made by our friend Roxanne in Florida. These have U-Haul padding inside and are very hard wearing when it comes to washing. They have been through hundreds of cycles and show no sign of giving up the ghost yet!
Carrying about and sampling(!) - If you''re carrying your guinea pig around from A to B in the house, you can use a Sterilite 0657 (White) plastic Dish Pan. They are available at many stores and online. However, they are in short supply recently, so don''t assume Walmart, Dollar General, etc. will have them. We recently got a couple more at a local Publix supermarket (for $2). Drop a small towel in the bottom, place your guinea pig in the pan and then place a small towel over the top to make them feel safer.Getting the White version is important. The Dish Pan can do double duty. If you need to take a urine sample, you can omit the towel and wait (and wait) for the guinea pig to pee. It can then be visually inspected first for colour and sampled for analysis by using a new, fresh syringe. Presto!