I'm not related to any of these shops nor branches, I simply buy there because what I like to use there is less expensive than at local shops in Malaga. Use at your own criteria.
I'm kind of partial to Stillman & Birn gamma, either A4 or A5. In Spain, the cheapest place I've found to buy them (shipment included) is on-line: Articomic. However, they tend to have only one unit available everytime (???), so it's probably better (for post costs) to go to Piera and buy several ones at the same time. Besides, you can add to your order Faber Castell Pitt sepia/sanguine markers and Pentel Aquash Aqua brushes, which are the ones I like to use and are cheaper to buy online.
Alternatively, if one goes for a cheaper sketchbook, I've used now and then Moleskine watercolor ones (only the watercolor ones (pink label), I kind of hate the paper in all the rest!). In this case the cheapest option used to be Book Depository, because they have no shipment charges. However. since the business changed hands, it is advisable to check other options first.
Originally, I used TRIA, since you could reload them and stuff. However, finding recharges for TRIA is so difficult that I swapped to Flexmarkers. Actually, I didn't use the third nib of TRIA that much ...
If you are studying at the university or work in education, probably the best place for you is Letraset itself. Shipment costs are not that high (and if you spend enough money, they are free) and they give a discount to anyone in education. Actually, Cowling Wilcox (UK) is usually quite cheaper, but they increased their shipment costs from 5 pounds to more than 20 a few years ago, so unless you are going to save big bucks, it makes no sense to buy online there any longer.
However, if it's too late for you and you are already loaded with super-expensive TRIA, not even Letraset carries its own cartridges. You might want to visit Jackson's Art for these. They are not too expensive, but shipment costs only make sense if you are going to buy more stuff. This makes sense if we move into ...
I do like Schmincke watercolors, but I use Cotman now and then because they are way more affordable. If you need to replace your Schminke half pan, Cowling Wilcox would be my choice, but if we add shipment costs, it's back to Jackson's Art for me (or Piera, I usually compare prices).
Please, note that depending on what you are planning to order, it might make more sense to pack everything together even if it's slightly more expensive. Thankfully, not every online business have Amazon policy to place each item in a different package and charge you for shipment costs for every single one :P
General online shops in Spain:
There are several shops at Spain that offer similar prices (competitive, with respect to physical shops). These are interesting for people in Spain because shipment costs are cheaper. Most of them offer free transportation if you go over a cost threshold, ranging from 70 EUR on. Otherwise, the main differences among them are not usually in the product cost, but in shipment costs and stock. Here are a few I've tried:
|Shop||Stock||Shipment Costs||Minimum for free delivery|
|Arte Miranda||Medium (eg. no Faber Castell,
Caran D'Ache or Stillman Birn
|4,50 EUR min||60 EUR (Spain)|
|Articomic||Limited (good for markers, has
Stillman & Birn)
|3,99 EUR min||50 EUR (Spain)|
|Barna Art||Good (no Stillman & Birn)||9 EUR min||95 EUR (Spain)|
|Piera||Very Good||7,20 EUR min||75 EUR (Spain)|
If anyone knows of any place where I can buy stuff cheaper than in the referred places, I'd be very much obliged for a link!