To some, Costco is just a big warehouse they drive by and have no idea of the wonders inside.
Even its members probably don’t know everything the retailer offers, or how to make the most of the bargains.
You might expect to find everyday objects in bulk. And yes, they do sell 40 bottles of water for £3.30 which works out at 8p a bottle.
But did you know Costco also sells everything from freshly-baked cakes and diamond rings to balloon rides – and you can even get your eyes tested there?
And note that there are members-only savings available at the Costco website - open to everyone, not just members - throughout January 2018.
Costco is the second biggest retailer in the world after Walmart, with 731 branches throughout the world and 28 in the UK.
One of them is in Birmingham, in Watson Road in Nechells opposite Star City.
Here’s some surprising information about Costco and the hacks you need to know to make the most of your shopping experience.
1) You can get free coffee and cake
If you turn up from Monday to Friday, between 10am and 11am, you can bag a free tea or coffee and a slice of cake.
2) The Birmingham store has a secret exit so you don’t get stuck on Bromford Lane Island
The Birmingham Costco is on a dual carriageway which means you enter and exit going east on the A47 Heartlands Parkway.
If you want to leave and go the other way into the city centre, you might think you are forced to go all the way to congested Bromford Lane Island to turn round.
But you don’t have to sit in queues of traffic, because there’s another exit. Drive through the basement car park and you can get out on the Star City island.
3) How to spot you are getting even more of a bargain
All Costco prices are low, but sometimes they’ve been reduced even further.
If the price ends with 97p, rather than the usual 99p before VAT is added, then it’s been reduced.
A cross on the price tag means it’s the end of the line and an offer that won’t be repeated.
4) Look out for the Kirkland brand
Costco has its own signature brand called Kirkland so is cheaper. The best bit is the items are often made by name brand companies, like Huggies and Grey Goose, for much less money.
5) There’s an in-store bakery
Head to the back of the store to get fresh fruit and all those pastries and cakes made from scratch every day in store, as well as freshly-produced pizzas and hot rotisserie chickens (£3.94)
You can order a customised cake (£13.99) with your own inscription and decoration from a football pitch to a caterpillar or dinosaur.
Halal lamb and chicken are new additions.
6) Avoid peak times
The store is pretty busy all day long but it is most congested at noon and 6pm every day and at the weekends.
Tuesday and Wednesday mornings are slightly quieter.
7) Look out for free samples, roadshows and seasonal goodies
Most days, between 10am and 5pm there are demonstrations in store and free samples to be eaten – and you can eat as much as you want.
There are also roadshows, pop-up travelling stores selling things like Krispy Kreme doughnuts which are there for just a week before moving on.
There are Halloween products in store at the moment, like a lifesize animated butler of Macabre Manor who lights up, moves and groans for £87.99, or the flicking pumpkins (£32.99).
There will soon be lots of Christmas products in store, like the huge teddy bear that’s almost eight feet tall. That is so popular that it even has its own Facebook page.
That costs £249.99, but on sale at the moment are the bears more than four feet tall for £39.99.
8) You can hire a van
There’s usually a van on site which you can drive away from £15 an hour.
Perfect for taking home a bulky item, or for moving anything without having to hire a ‘man with a van’.
You can have it overnight from £30 or for the whole day from £70.
9) They also sell hot air balloon rides
Costco also sells experiences, like the hot air balloon ride you can take whenever you want – half price at £99.58.
Or you can try clay shooting, spa days, helicopter flights, golf days and two £20 Pizza Express vouchers for £33.99.
10) You can get your eyes tested or buy a new tyre
You can get your eyes tested by opticians and buy big brand frames at bargain prices.
And there’s a tyre centre selling tyres, repairing punctures and offering free pressure checks.
11) It has a cheap cafe
The best deal in the cafe is £1.50 for a substantial hot dog with a refillable soda.
The gelato is new and you get three giant scoops for £2.
It’s not just cash and carry.
You can’t use credit cards apart from American Express but you can use debit cards as well as cash.
12) Most people can join
The Birmingham Costco has extended the eligibility criteria for members.
Strictly speaking you are supposed to be a employed in sectors such as banking, legal, health, civil service, education, insurance, emergency services and so on.
But at Birmingham there are new membership categories which also includes card holders with the RAC, AA, National Trust and American Express.
The annual membership is £33.60 but if you join now you also get a £10 voucher and coupons.
And if you’re not a member, you can shop by tagging along with one – or shop online.