To clean up my advice above, prepare 230 g of dextrose in 100 ml of clean water. Heat gently for 20 minutes stirring constantly to avoid caramelization. The resulting syrup will reduce somewhat. Allow it to cool. Use in quantities as directed by your recipe.
Source:
http://www.thbs.intas.net/p_f_sugar_dextrose_syrup.htmI, too, have been looking to cut costs. It's silly to buy the smaller bags for regular liqueurs if one has a large sack of dextrose.
The recipe above can be doubled or otherwise extrapolated as necessary with any leftovers saved for next time.