"although expensive" is a correct and usable part of a sentence in written English.
You can use it when you want to mention something is costly despite its benefits or qualities. For example: "This laptop has incredible features, although expensive."
The loans, although expensive, nevertheless seemed to encourage investors.
News UK's decision not to reclaim costs, although expensive, means it avoids a potentially damaging and protracted scrutiny of its stance during and before the trial.
Accessible buses are well ahead of the timetables in the Transport Standards, although expensive rail and tram infrastructure is not keeping up across the country.
Although expensive to ship and store, peat nevertheless provides a small percentage of Finnish energy and is also used in agriculture.
Although expensive dessert wines known as vendange tardive (late harvest) and selection de grains nobles (selection of noble grapes, equal to German berrenauslese) can be glorious, the dry, spicy whites are daily workhorses with the region's delicious Germanic dishes.
Although expensive dessert wines known as vendange tardive (late harvest) and selection de grains nobles (selection of noble grapes, equal to German beerenauslese) can be glorious, the dry, spicy whites are daily workhorses with the region's delicious Germanic dishes.
It is quicker and more reliable – although more expensive and wasteful – to change the tube.
Although more expensive to buy, electric cars are cheaper to run than conventional ones.
Although staging expensive grand opera is increasingly rare, Moshinsky rejects suggestions that the art form is on life support.
The course at the Banyan Tree resort is typical of the great Thai courses, although more expensive.
Those without retiree health benefits who are eligible can use a patchwork of federal and state laws to build an insurance bridge — although an expensive one — to Medicare.
