Tulum is a place full of contradictions. It has one of the most gorgeous beaches we've ever seen, the atmosphere in the town is quite backpacker'y and there are places to eat quite affordably in the town (which usually is not the case on the Caribbean coast) However, Tulum is also the place of exceptionally expensive accommodation on the beach - almost the entire strip of the beach is full of boutique hotels and cabanas where you'd pay minimum of $60/night, and the out-of-the-hotels restaurants on the beach will charge you triple the amount you'd pay for the same stuff in the town or in smaller Caribbean coast villages/towns (e.g. a fish meal may cost $20-25)
Tulum town is located by the Chetumal - Cancun highway and that's about 7km from the beach, hence the difference - hostels and eateries are in the town, expensive hotels and restaurants are on the beach. We, however, came up with a pretty sweet compromise to stay on the beach.
South of Tulum ruins (famous Maya ruins right by the sea) there is the public beach that is closest to the town. It stretches for about 3km and has about 4 of those expensive restaurants and some cabanas. If you go to the last entrance to the public beach before Maya ruins territory and walk back on the beach - you'll spot a bunch of basic looking cabanas, some of them looking like they've been dug into the sand dune. Thats where you'll find the cheapest accommodation on the beach - cabanas on stilts for about $28 and very basic ones that look like bunkers - for $20. Thats where we stayed and got stuck for almost a week. Basic cabana means just a shack, with a bed, mosquito net, table and 2 chairs, walls are made from driftwood sticks which leaves plenty of cracks and sand in the room. There's no electricity, only a candle, and the bathroom/showers are about 50m away. Sounds a bit too extreme for a beach holiday? :) Well, it's definitely a life hack - you stay right on the gorgeous beach without paying $60-200 per night. You can also take a tent and just sleep on the beach as well.
Another hack we did to avoid paying $50 per day for meals - we went to a supermarket in the town and got food supplies for 4 days. Had to pay $7 for taxi (thats what the distance between the town and the beach costs, there are also collectives for 10 cents, but they really seem to be phantom ones) The taxi was worth saving all the money on food. Of course the food would need to stay good without the fridge, so it was mainly tortillas, avocados, tomatoes, canned tuna, canned veggies, bread, salted cheese, sweets, etc. So instead of going to those pretentious restaurants we had a sunset picnic on the beach every day.
Tulum beach is just incredible - perfectly white sand, long wide beach with palm trees and dunes. Relatively less people, and the best part about those people - they start to disappear around sunset - all those on a day trip leave, all those staying in the town leave, all those staying in the hotels leave, so at about 8-9pm there usually were only us and a couple of other moon watchers on the entire strip of the beach.
Sunset watching followed by moon watching is an amazing experience in Tulum. We were lucky to be there during full moon which made the views over the sea into simply unbelievable beauty. The night beach was lit by the moonlight, water shimmering with silver reflections, boats rocking on gentle waves, night sea breeze in your nostrils. Amazing!
The sunsets were also one of the most gorgeous ones we've ever seen. Every single night the nature performed a completely different sunset show for us - light & ice creamy, heavy and stormy, bright acid colors, foggy and mysterious. Sitting on the beach at sunset was like going to an art performance every night.
The water in the best Caribbean tradition went from transparent to bright turquoise to deep blue during day time and silvery at night. Needless to say - it was warm and pleasant. Plus, a bit of waves definitely added fun for us.
All in all, It's an absolutely beautiful place regardless of it being one of the top tourist destinations on the coast.