You're only looking at $35 for 500ml, less discounts/sales of 15 to 25% off which happen nearly every weekend.
Reload can be streaky, best applied as drying aid after wash as noted above. Longevity on a driven car is not the greatest, a month or 2 tops but on fair-weather-only car it'll be longer.
100ml is really kinda sample-sized. If you drive car often and is exposed to rain or frequent washes, get 500ml.
Reload and other products of its nature are kinda like Quick Detailer or light spray wax equivalents for coatings. Adds a bit of gloss and entertaining water behavior.