This league without Lewandoski wouldn’t be the same. He is the best striker and for that reason the most expensive one. If you think that he is not fast enough, you can replace him by Werner. However, don’t expect to score with the head so often.
Volland and Kramaric are both slow but good finishers. Players like Bas Dost are too slow and should be avoided. Mario Götze is a decent player but should be used as a CAM or at leat as a CF. For low-budget teams, there are sveral good options, like Córdoba (strongest), Paco Álcacer (#3 shooting), Mateta and Pléa.