The hassle and cost of renting off-site (Uber will likely be >$20, so your savings will be <$30, if not smaller) would negate it for me. You're much less likely to get an upgrade or any choice off-site. If the overall savings is more than $75 and the hassle is minor, then I'd explore it. Also, if your flight is late, will you miss the pickup times of the off-site location?