Deal Dash is a really great way to score some stuff in my experience, but beyond the simple mechanics of how it works, a few other bits of advice before you go nuts:
1) Observe, observe, observe! Nearly every item up for auction will come up for auction again. Especially when you are starting out, watch and learn who the big players are and how they are bidding. You are going to get blown out of the water and have a bad experience if you spend what you consider a lot of bids, only to lose against someone who was always going to bid way more than you could. The joy of Deal Dash comes in those miracle wins when no one is watching.
2) Don't expect luxury items because you see luxury prices. Particularly with the recurring brands that you see constantly - the ones that present as a luxury brand but you've never heard of until now. Everything I have won is quality, but it's not luxury quality.
3) Realize that the retail prices Deal Dash displays are massively inflated. You might see that as a bad thing, but consider that this also prevents the top players from blowing every single auction out of the water with massive numbers of bids, knowing that they can "Buy It Now" for a much smaller and more realistic retail rate and get all those bids back on top of it.
4) It should go without saying, but stick to a budget. Deal Dash is entertainment money. It is not going to help you make ends meet if you are struggling. There are very few items on DD that anyone really *needs*. I've seen people waste colossal amounts of bids (way more than they could earn for free), and yet these are some of the same people whose profile implies they are struggling.
Don't be dumb, and Deal Dash may turn out to be a lot of fun!