100k minimum for an inbound channel is actually a lot less than most providers require. I run my own node and the minimum was a 500k inbound channel. Once you purchase the inbound channel, just transfer 100k or more sats to your node and it will be available as outbound capacity. The only actual expense is the fee for the inbound channel, about 15k sats last I looked, although it may be less for a channel with only 100k capacity.