The spyglass is probably priced high to represent the difficulty of making it in a proto-medieval world that is the default D&D. Adding it to a game or reducing its price would have very little impact on a game.
Depending on the type of campaign, adding a flat 1,000 gp to the party really wouldn't hurt it at all. A gritty, realistic game would have problems, but the heroic game wouldn't be much of an issue. The most they'll do is start with some Breastplate or Splint armor, which is basically a +1 AC to a couple of characters, or save it for one character to get Plate armor in a while. If you allow unlimited purchase of Potions of Healing (which IMO you should not), then they could start with 20 of them, which would probably unbalance a level 1-2 game.
Depending on the type of campaign, adding a flat 1,000 gp to the party really wouldn't hurt it at all. A gritty, realistic game would have problems, but the heroic game wouldn't be much of an issue. The most they'll do is start with some Breastplate or Splint armor, which is basically a +1 AC to a couple of characters, or save it for one character to get Plate armor in a while. If you allow unlimited purchase of Potions of Healing (which IMO you should not), then they could start with 20 of them, which would probably unbalance a level 1-2 game.