I'm looking for a good reservation site (we are going to Barcelona for a vacation, yaaaa!). all the 'big' ones (like hotels.com, Travelocity, Expedia and their like) look much the same to me with very similar prices. do yo know of a really cheap one?
I made some research and found some small and cheap, yet unknown sites - for example like: http://bit.ly/2M7uEV but i don't know if these can be trusted. what say you? any good ideas for me? many thanks!

I think you have a major misconception about how hotel booking works. The booking sites deal mainly with chains, though there are certainly some independent hotels affiliated with sites like Utell.com. OctopusTravel.com also has a lot of smaller independent hotels. I've also booked through Hotelclub.net, but since they were purchased by Orbitz, the number of actual deals offered isn't that many anymore.

The hotel sites have similar prices because they are all pulling from the same inventory of mostly chain hotels. And unfortunately, you are not going to find some magical deal on an expensive hotel just by booking through a small site. Prices are what they are. Having said that, there are some very good discounts right now, and if you do a little research (i.e., find some knowledgable travelers to recommend a great inexpensive hotel or buy a guidebook and do a little reading up on Barcelona), that's the best way you're likely to find a good deal.

Priceline might also offer some deals on Barcelona asy ou approach your travel dates, but you're gonig to end up in a big chain. If that's what you want, then great. But the cheaper hidden hotels don't generally belong to these big booking networks. They do business through word of mouth and are cheap because they are cheap, not because they offer phenemonal discounts through a travel booking site.

You sometimes get a big discount by booking a package that includes both hotel and airfare, but then you sometimes get stuck in an out of the way location in a mediocre hotel.

My own method, I have found the cheapest hotels by doing research on internet travel forums, asking questions, (here on Fodor's & also the destination forums at Trip Advisor & Thorn Tree on Lonely Planet). When when I find a place I like, I book directly with the hotel.

Like Doug mentions... the very cheapest hotels aren't even listed on Priceline, Hotwire, Expedia, etc. because they are likely small, budget, local-style places. Hotels on those sites (it's just the nature of the beast) even the cheapest are more expensive than truly inexpensive lodging... if that makes sense.

For Europe, you can usually find decent budget hotels on venere.com and eurocheapo.com, and some are listed along with hostels on hostels.com. For some nice places that are a bit more expensive try www.sawdays.co.uk .

I would only use the big sites in big cities, and even then they often list really grim places, or places that are still too expensive.

we had a great results from www,hostels.com also had a very reasonable hotel los Arcos on la Ramblas barcelona.