In my novel, the fantasy world is a gold mine for arms dealers, governments and ordinary companies to sell their share of goods to the fantasy world. Being a military geek, I can list out a ton of weapons waiting to be sold to the other side of the portal but what about more ordinary items? What will they bring to the other world? How will the occupants in the other world react to this? Will they prefer guns to wands? Or will they just see radios as a stupid gimmick only?
It's going to depend on what magic is readily available in the fantasy world. An electric torch would be less useful if everyone can cast light spells. And also what technology and resources are available in the fantasy world. Potentially saleable things include- Civilian vehicles. Cars, motorcycles bicycles. Fuel, electricity, batteries etc for whatever technology is sold. Construction equipment. Food and drink- baked beans and Coca-Cola marketed as exotic delacies from the other world. Medicine, to combat all the new bacteria that gets brought across. Tobacco
You may also want to consider the fact that a pre-industrial society would lack the means to power electrical devices, and that they won't have fuel refineries. A common, but logical, trope is that ambient magic fields disrupt more delicate technology. And @plothog is right: they do already have magic. How reliable is it? How accessible or common? Is it something only an elite few can do, like in LOTR? Or can everyone do it, with the right training? Or, can non-mages go into a shop and buy charms, potions, etc? In a world of used broomstick dealers, discount talismans and crystal ball service providers, Earth technology may seem clever, but unnecessary.
Err... That wouldn't work because the multi-national military force from Earth are supposed to use modern weapons and equipment just fine...
Okay, so you have given more information to work with. However, "modern weapons and equipment" simply will not hold up in this alternate world for one very good reason - it is a different world. Most modern military pieces will probably not work well in any "non-Earth" set up due to geophysical/navigational-related differences. Compasses may be useless, GPS is out of the question, logistics would be a beast depending on the set up. Also, the first "active defense" magic would wreck most modern weapons the same way they are doing so in real life. But I trust you have already done such work... A market of "ordinary items" would serve to go and replace/upgrade/fit any need of the world that is currently unable to be filled by a lesser means. Plothog is really spot on here. Though the effects are really something which is based on the society and the state upon which such interactions occur. It is very complex and we cannot possibly write what you would want, try and develop the question a little more. Even something like "guns vs wands" comes down to military efficiency vs magical ability. As an example, say we have "Harry Potter" level of magic. Setting aside how unrealistic as it is to have one spell for killing, wands would be carried by EVERY capable soldier because they can do other functions and are small. The "pew pew" of guns would be great in combat, but aside of some bullet barriers - wands will be secondary or tertiary weapons. This is a reason why soldiers carry knives, they are not just for getting on with stabbing and the bloodletting - it is an essential survival tool. Also... knives, fantasy worlds would love a high-quality stainless steel set of blades.
Sell them cars and generators for cheap, but gouge the price on fuel. Same with guns, make them dirt cheap, hit the up with the cost to use. If magic exists imagine how much more damage a gun can do if the bullets are blessed. Figure in sin items, tobacco, drugs, booze. introduce processed food and pizza. Synthetic textiles, advanced armors and stronger steels and better alloys all for the highest bidder.
100% depends on the versatility and advancement of the knowledge. Magic can pretty much be used however you like, so it all depends on how you set up your system. It can go against the laws of reality after all. Here's a few areas which may be of interest to them, again depending on what magic they already possess. For all I know you have magical creatures as well that can serve some of these functions. Agriculture: If everyone is farming for their food than giving them tools to increase crop-yield or selling information on certain techniques could be lucrative (irrigation, crop-rotation, etc.). Sanitation: Aqueducts, sewer systems, etc. Hell, you could sell Life Straws if it's hard to find clean water at certain locations. Television: Most likely this will be of interest to nearly anyone. I would assume you would have to use either hand-cranked, solar powered, or battery powered TVs with a DVD player set-up. Clothing: With our ability to mass produce clothing it could easily replace their methods if they have limited production capabilities. Since we can also produce plenty of thermal wear, it could be beneficial in colder regions. Even higher quality shoes that are measured out specifically for each person instead of guess work. Cosmetics/Beauty Products: Women are women anywhere you go. Same would apply for jewelry, art, etc. Glasses/Contacts: Unless there's a spell to fix someone's vision or if the magic repairs the body in general, these will help those who have problems seeing. Portable Camping Gear: Tents, generators, kitchens, etc. For refuges these items can be invaluable. While nomads can move from place to place and set up camp, it's still a lot faster with our level of technology. Food: If their main source of food is agricultural based, than canned food could be an easy sell.
So true! I'd bet they'd love refrigeration, provided electricity was available. Food born illness has long been a major killer. What about antibiotics? Major quality of life advancement there. In the time period I'm working with they'd probably be ecstatic over toothpaste! (Specifically the kind with fluoride. Most adult human skulls found in burial chambers lacked teeth unless there were in a area that had naturally occurring fluoride in the water.)
